User blog comment:Maddyfae/:D Excited!!!!! :D/@comment-3319309-20110319034054

This is what the canon wiki says:

"It's Phineas' birthday and for the special occasion, Ferb puts together a clip show of the gang's favorite moments. Candace however wants to use the clips to finally bust Phineas and Ferb. Meanwhile, Agent P must stop Dr. Doofenshmirtz from using his 'non-inator' to pre-empt his brother's biography from appearing on television."

So it is about Phin's upcoming b-day.. There's also a pic with creepy balloons that are supposed to look like Phin... O.o