Maybe too late, but tomorrow night (July 16) at East Brady. The town is having "RiverFest 2011" at the upper end of Pool 9.
That is a long ride from Pittsburgh, but well worth it. Making it even more worth it is that after this summer, there won't be anymore locking through since they are closing the last two locks. If I wasn't on-call this weekend, I would consider making the ride up.
We stayed at the Kittanning Marina which is just above Lock 7. We made it that far on a Friday in 4 hours. Did the last 2 on Saturday and stayed at the Kittanning Marina Saturday night as well. Left on Sunday when the lock opened and was back in the Pittsburgh Pool by 6PM. It was great!