As ‘the guy’ helping my friend set up her birthday party, it’s my responsibility to figure out how to hang the pinata. There are no exposed rafters or anything obvious to hang it from, so I’ve considered two options: hanging from the ceiling, and hanging by a line strung between two walls. In either case I would need to install anchors–I have ones that work pretty well that screw in by hand, and then I could screw in a hook or something. If I put a drywall anchor in the ceiling, how much weight could it likely support? Should I attempt by find a rafter… by tapping on the ceiling I guess? Or would it be better to string a line between two hooks on opposite walls? The pinata weights a little less than a gallon of milk, so maybe five pounds.
Don’t over-think this stuff or cause physical damage to the house because of a kid’s game. Just buy a long wooden dowel like a closet rod or something similar, hang the pinata from the middle and get two adults to hold the rod. What you are leaning towards might cause real damage to the walls.
Don’t buy anything at all–just use a broomstick. The kids won’t even notice; all they’ll be focused on is what’s inside, and how fast they can get to it.
What kids; we’re all 20-22 
Note that the broomstick idea puts the supporting folks in range of the hyped up blindfolded kid swinging a stick…so if you go with this, be sure to have a video camera rolling so that you can try to offset the cost of the ER visit with prize money from “America’s Funniest Home Videos”
Definitely hang it from the sprinkler head then.
How heavy is this pinata going to be? A little hook in the ceiling, especially a white one, can go unnoticed or be used to hang a fern later.
If you use the broomstick to hold it, what are you going to hit it with? 
Just remember to keep the video camera rolling at all times.
Despite what you see on TV all the time, piñatas don’t just hang there. You need to hang it so that someone can hold the line and move it around while someone else is trying to whack it. That’ll increase the mass you have to bear.
Get the people drunk enough it’ll look like it’s moving by itself.
We once attempted to destroy a piñata in a hotel room (a non-wedding bachelorette party… sort of). We had Spongebob Squarepants hanging from the air vent in the living room of the suite. It didn’t hold up very well, and every hit would just send it flying across the room. We were entirely unable to break it open with the small stick we had, nor with the tennis racket a friend happened to have (and she’s played tennis all her life; she has a good swing!)
We finally just grabbed a giant kitchen knife and let the person for whom this party was being held stab the hell out of Spongebob! It was particularly therapeutic for her, seeing has how that Sponge has the same stupid grin her ex had!
Unfortunately, most of the candy containers on the inside were torn open in the process, but you should have seen the look on her face, and on her friends faces as we all dug in and tore that thing to shreds. It was a lot of fun!
Just hang from the ceiling, yourself, and hold the pinata.