We have been learning tricks lately, too. I hope to start therapy dog work with Grumpy soon and the people we visit will want to see some tricks!
Grumpy does the "pick a hand" trick mguiette mentioned... she will also nose or paw any object you point to, we say "touch" for the paw and "target" for the nose. (We learned this in therapy dog class... eventually they will teach them to flip light switches, open doors, etc this way, like service dogs.)
She also knows "say your prayers" - standing on her hind legs, front paws resting on a chair, chin down on her front paws. So cute

To teach it you just lure the dog with a treat to stand up, paws on the chair (not hard, most dogs do this anyway!) and then pull the treat down to their front paws until the chin touches. Once the get that, you can add "wait" and see how long they can hold the position.
We also taught her to back up (harder than it looks!) by just holding the treat to her nose and stepping forward. At first she would just pivot or move aside, but eventually she got the idea of moving her back legs and from there it was easy. Once they can back up, you can teach your dog to "dance" with you

Stand facing your dog, when you move forward, she moves back, and vice versa. Grumpy loves to dance and she'll follow me sideways now too.