Here's a cool thing to do: On your birthday, ride your age! Gives you something to work towards. Impresses the heck out of your friends!
Too funny. I've done that with running for years, although I didn't do it for the last 3 (I am now 39). Running 40 for my 40th would be grand!

I'd sit in the tub and admire my muscles after the run and thank the ol' legs for serving me so well for so many years.

No reason you can't do that after a ride. A glass of champagne would be nice too