Jeez, how could we forget straightening out the Leaning Tower of Pisa?
Or make it lean the other way.
I’d use my superspeed to give Michael Jackson his original face back.
Of course since you’d be polluting the lake Bill Gates lives on all you’d end up doing is creating a super-enemy along the lines of Lex Luthor. A mad genius with massive amounts of monetary and technological resources at his fingertips. Better to fling the cars up into orbit or smash them into almost unrecognizable shapes and make art deco on the bridge. May even win a city beautification grant.
Enjoy,
Steven
I’d just hang around major downtown intersections, getting off bad one-liners, making lusty remarks and refusing to go away. An all-world wise ass. Whenever anyone honked a horn, I’d scream AHH-WOOO-GAAHH! Sometimes I’d go into offices and loudly read Remembrance of Things Past in really bad French from start to finish. I’d take off everybody’s clothes over and over and over again until they didn’t bother putting them on anymore. I’d collect millions of the slimiest insects – roaches, centipedes, huge slugs and cram them all into my Tardis-like mouth. Whenever I ran into another ass (five seconds or so) I’d give him a blast. Maybe 100,000 insects per ass. There are a million things you could do.
With my super-invisibility, I’d hang out in elevators. Whenever only two people were in a car together, I’d stand between them and release silent but deadly super-flatulence. Each would think the other did it, you see! It’s brilliant!
I would arrange for all television sets and monitors in the world to simultaneously show the Church of the Subgenius recruitment/indoctrination video Arise, on a continuous loop from beginning to end.
During the Super Bowl. 
I would roam the remotest places of the world, convincing the natives I’m a god and demanding they offer me their virgins. Oh, and their sluts, too.
Aww, Bush harassment was the first thing that popped into my mind, you beat me to it! Well, while invisible at super-speed, I’ll sneak hefty doses of laxatives into everything he’s likely to eat or drink. But I’ll warn you first, so you can time the goosing appropriately. 
I’d break into the houses of people I don’t like and burn all the labels off their canned goods, scrambling the cans on the way out.
Just pack my own sandwich, and eat my lunch every day…
…in the world’s most “secure” locations. You know—the Oval Office, the Cheyenne Mountain Command Center, the Pope’s bedroom, etc. Don’t even acknowledge anyone’s presence/reactions/hail of gunfire, just quietly eat.
Pretend to unsubtly use my X-Ray vision on pretty ladies, then walk up to them, tell that what I did, and…very somberly suggest they visit their doctor. I mean, I’m not an expert, and I could be and sure hope I’m wrong, but…I saw some “stuff” that looked alarming. I’m very sorry.
Do some really amazing, superheroic stuff that saves thousands (or millions) of lives to reveal my presence to the world…and then “reveal” that, to keep my superpowers, I require blood sacrifices.
I’d use my invisibility to totally mess with people. I can’t even begin to go into the huge list of ways I could do this, I just know that it would be so. much. fun.
I’d see what kind of damage I could do with 3,000 MPH spitballs. I’d dress in civilian clothes, randomly walk into traffic on the interstate or stand on the ledges of tall buildings and threaten to jump off. I’d feed elephants laxatives, and then fly them over busy interstates. I’d fly by jets and fake getting sucked into the engines.
Ah, planes. That inspires me.
Another good plane one : Grab onto a wing, and act like you are desperately trying to hold on until people see you. Then let go.
Or use a combo of X-Ray vision and superspeed to recreate that old Twilight Zone episode with the creature attacking the engine. Use X-Ray vision to make sure only one person is looking and start tearing and pounding at the engine like you are trying to destroy it. When anyone else looks, zip away too fast to be seen. When they look away, zip right back at start pounding again.
Another : Smoosh your face up against some random plane passenger’s window glass and make goofy faces at them until someone notices. Then fly away before anyone else sees.
Or, smack into the cockpit window, hang there limply for a few seconds, and fall off.
Or crawl up onto the cockpit window from below with a horrified expression. Claw and bang at the window, then “lose your grip” and fall away.
That’s not jerkish, the face he now has is an abomination.
I’m sorry, worst I can come up with is sit on planes and let them carry me. I mean, stuff like proving the depths of infamy to which some political parties fall and who exactly was involved in each specific breach of the law is do-gooding.
Okay, some of you guys are way too good at this.
I would turn off the Internet. For a week. Moahahahahaha!
I’d stick icebergs in front of cruise ships and then snatch them away at the last second, while a stereo blasts My Heart Will Go On at full volume.
Transport some polar bears to the South Pole and plunk them down in front of penguin photographers.
Let out super farts during speeches by the Pope.
Dress in civilian clothes, go to the zoo and throw myself into the various pens of vicious animals.
Hey, they might not know what it is, but at least it’s cooked!
I’d remake the moon into an exact image of my ass.
I think I just figured out the most frivolous thing to do with my SuperPowers…
Nothing.
Nothing at all.
What’s more jerkish then having ultimate power to do things for ‘good’ (or atleast prevent ‘bad’ things from happening), than to do nothing at all?
Then all these people could be constantly asking me why I let bad things happen to good people when I clearly had the ability to do good?
Perhaps if they asked me more often, or more of them asked me to do stuff, I would, but only if I thougth they deserved it, only if those asking had asked in just the right manner, or only if I agreed with what they wanted. Then I ‘might’ do
something.
Then I’d just remind them… I’m following a higher power’s example…
And they’d rightly call me a jerk.