I haven't for my cat, but I don't see anything wrong with getting your kitty extra treats and toys on his/her birthday! How fun

Maybe some cake for the humans in the house too!
I celebrate Cramer's (Solomon Island Eclectus) hatch day and gotchu day. His hatch day was 12/5/04, and his gotchu day (the day we picked him up at the airport) was 4/18/05.

He gets parrot toys and extra treats (like mullet spray). And yes, bites of cake too. Just a little.