I just Googled "biggest Presidential birthday parties" and came across an article in the August 4, 2009 issue of Time Magazine. They listed a few of the more notable parties that had occurred, basically listing them as a backdrop with which Obama's low key birthday celebration in 2009 could be compared favorably. The implicit message was obviously that Obama is a President who works hard and doesn't have time for any of that nonsense.
Obama's subsequent birthdays, both this year's and last, have contradicted that supposition. In fact, this week's celebration has made me wonder: has there ever been a President whose birthday has been a more festive occasion?
The Time article cited above listed a few. John F. Kennedy famously had Marilyn Monroe sing "Happy Birthday Mr. President" to him at his 45th. Bill Clinton's 50th was a large affair at Radio City Music Hall. FDR's 52nd was evidently a large production at NYC's Waldorf Astoria Hotel.
But I honestly can't recall any Presidential birthday celebrations which lasted more than one day or which involved as many show business people as the one this week.