RAM Mounts are an American company who make a mounting kit that revolves around two balls and a connector. You put one ball on your kit (camera, GPS, gun) and one on your 'thing' (bike, car, tank) and use the connector to... connect them.
They are simple, reasonably inexpensive and just work. I've got a few RAM Balls on my bike which essentially turns it into a mobile camera rig. I don't need a tripod, I just use the bike. When I fall off the bike they don't break. When I want to go into a cafe for a skinny mochaccino I can take the whole thing off in seconds. I love them.