Hamster runaways are very common. It seems like these little critters' life goal is to escape. (I can see why, would you want to live your whole life in a cage?) Please, take your hamster out often so he doesnt always feel confined. Buttercup got totally antsy when spring came, I guess she got spring fever! (I'm surprised they can tell when spring is). Finding Buttecup has always been pretty easy for me, and she's gotten away numerous times. However, when Cupcake ran away she was gone 4 days and I almost gave up hope.
       A common way to find hammie again is to leave a little food in each room, close the doors, and see in what room food's gone. Then, once you find which room your hamster's in, use this trick. Get a bucket which is higher than your hamster can climb and fill it with bedding, food, treats, ect. Put it against the wall because hamsters tend to travel along the wall. Lean books up against it in steps so hammie can get in, but once he's in, there's no getting out! (Of course if you don't want to do this, you could just look for the hamster with a flashlight or whatever).
       Another way to find your hamster (this only works if you have a cage with a door) is to just leave the cage door open with plenty of food inside and then maybe hammie will decide the cage is the best place to be afterall. This works well if you have a cat or other big pet because the hamster will get so scared it realizes the cage is the safest place to be.
       For everyone who's hamster has been gone a little while, I feel your pain! See Devastated by Cupcake. She was gone 4 days and I panicked, but you shouldn't. She just turned up in my dad's office and that was it! I set up all the traps and everything and none of them worked so I don't know if it's worth the trouble unless you're sure hammie's in a specific room and can keep him there. Don't give up hope, just wait and listen. He'll probably turn up somewhere unexpected soon!