What's the best way to tell my husband I'm pregnant as a birthday present?

I'm pretty sure I'm pregnant and SO excited. It's my husband's birthday on Wednesday and I can't decide whether to just wait and do the test with him, or find out myself and then announce it in some silly way, like spelling it out on top of a cake, or doing him a silly card saying guess who's going to be the best dad in the world... Any suggestions? We've been trying in a very relaxed way for the past few months. I'm 1 or 2 days late and have sore , low cramping etc. No great tragedy if it turns out I'm not pregnant but totally fab if I am! THANKS!