I had fun shooting pictures at our company bowling night last night. Ideally in a bowling alley (or any dark place) I would have had a reflector-diffuser to avoid those hard shadows from my flash.
Here you can learn how to make your own reflector-diffuser. These work great. I have a friend that has made one and they create lovely soft indoor pictures. For a professional and compact one take a look at LumiQuest Quik Bounce, I just saw advertised in Photoshop User Magazine. I may have to get one for myself come Christmas.
Partially bouncing off the ceiling worked alright. Don't forget extra batteries for your flash when shooting at a dark location.
I hope you enjoy the pictures.