I had a chance to get out to Berkeley Castle last month during the University's excavations (run by the astoundingly good archaeologists Emily Glass and Sian Thomas). While the weather didn't hold the entire time, the students really got stuck in and did a fantastic job. I also got to run the one-day post-excavation session with a local school - those kids were a bunch of bright sparks and picked up the run of things quick smart.
Undergraduate students excavating:
The post-excavation third year helpers: