Happy Birthday, Emily! ---- (Still)

Emily's birthday was on June 22, which we celebrated here.  We had lots of balloons and the kids enjoyed playing with them.  They discovered that if they put a balloon over the air conditioning vent it would fly up and bob around until the air kicked off.  When they left for home this little balloon was still over the register.  Today is July 19 and this balloon has been over the register since June 22.  It goes up and dances around, then falls back onto the register until the air starts again.  We have left it there, wondering how long it will take before it stops this interesting little game.  I've been trying to upload a video of it, but with no luck.  You'll just have to take my word for it -- this balloon is in the air even though the picture doesn't really show it.