What's a decent Android app that lets you mess around with virtual instruments, like a guitar or keyboard?

Look, I'm no musician, but sometimes you just wanna noodle around. This Music Instruments Simulator app, it's...okay. It ain't gonna replace the real thing, obviously. The piano sounds kinda tinny, and the guitar is...well, it's a phone pretending to be a guitar. But for messing around on the job site when it's raining and you're stuck in the truck, it's not bad. The interface is simple enough, even with gloves on. Battery life takes a hit if you're playing for hours, so keep a charger handy. The tutorial is useless, just skip it. But once you figure out the basic layout, it's functional. I wouldn't pay much for it, but it's a decent time waster that doesn't require internet, and sometimes that's all you need.