Speaking of festivals (see my reply to Charlene), the Rittenhouse Row festival is May 18 this year. I like it because you can sample small plates from many different restaurants from $2 to $6. Quality and quantity varies.
The best of the last couple of years:
* delicious Ceviche from Pasion! restaurant; large portion for $4 (normal pricing is 2 for $17)
* Smith & Wollensky had a LARGE portion of steak au poivre (sp?) and creamed spinach. 2 years ago it was $2 since they were about to open; last year it was $4 and the portion was a bit smaller but still worthwhile.
* Founders had some nice rare tuna on a bed of greens with wasabi dressing; either $2 or $3
* Prime Rib had their homemade potato chips
* free samples (more corporate than local)
And some downers:
* several restaurants charging $5 or $6 for *miniscule* crabcakes or crabcake sandwiches
* too many restaurants offering the same variation of pasta salad