I don't do too much either. I do make cupcakes for the afternoon snack though. This year I made little party hats for them to wear and I buy them a book for their gift. I also, have 3 kids who bdays are at the end January that are within a week of each other so we do one big celebration. Then my own son's bday is on Valentine's Day, so I do his at the same time as the other 3 so we can focus on V-Day and I'm not making a tonne of cupcakes.
My two other dck's bdays are in September and are two weeks apart, so I will probably just do the same thing as I do in January and do one big party for them.