If I had Flash’s power, I would set a new world record for plate spinning.
If I had Rogue’s power, I would steal test answers from my professors.
If I had Jubilee’s power, the annual fireworks show would be both better and cheaper.
A friend of mine had his character do this in a superhero RPG that I play. I think it’s a great idea:
It requires shapeshifting powers (Mystique, Beast Boy, etc.), and a friend or roommate. When some unwanted solicitor comes to your door, get the friend to throw it open and shout “Release the lion!” Immediately shapeshift into said lion, and go bounding out the door at the hapless victim, chasing them away. Hilarity ensues. 
If I had Wolverine’s healing ability, I’d go to a biker bar and ask the toughest looking guy there, “Hey, aren’t you Richard Simmons?”
With Jedi mind control powers, I’d tell the IRS, “I am not the taxpayer you’re looking for.”
If I had Colossal Boy’s power, I’d paint myself green and work to convince children to eat their vegetables. *
If I had Triplicate Girl’s power, I’d hang out in the mall outside Lenscrafters and see how many people I could make go right back in the shop for a re-fitting.
If I had Karate Kid’s power, I’d wax my car, paint my fence, sand my floor…
*(“Yo ho ho! Green Giant!” Too obscure?)
If I had Lightning Lad’s power, I’d short out the car stereo system of everyone whose music can be heard beyond the walls of their actual car.
If I had Saturn Girl’s power, I’d be able to figure out whether my six-month old daughter is hungry, or wet, or just wants to play, or whatever.
“Wow, Lois, you have a really sexy pair of kidneys.”
Damn freakin’ right. Actually, all the superpower I ask is the ability to melt speaker wire at 300 yards. THUMPA, THUMPA, THU…[blissful silence]
If I had Iceman’s power, I’d have a LOT of fun at Raging Waters. I’d be watching little kids going down the slide…
“Mommy, lookit me, lookit meeeee THUD”
If I were female, and had Elastigirl’s stretching powers, I’d set a world record for the fastest labor and delivery.
What a lovely bouncing baby boy!! LITERALLY!!!
If I was The Beyonder, I’d create my own universe where time goes by at a billionth the speed, where I’d go to get an extra few hours of sleep in the morning, or just to take a cat nap when I’m working.