In reply to Flying Spaghetti Monster:
This is an eternal issue for me, as the big teacher holidays fall at a time when most well known european sport destinations are too hot. The classic venues are Ceuse and Rodellar, but the crowds keep me away.
It depends what grade you are after, but you could do a lot worse than getting the Schweiz Extrem guidebooks, and heading to Switzerland. Lots of great crags that are high up and cool (Simplon Dorf is a great example). And you get the added bonus of lots of multipitch routes if you want them, and obviously great walking and mountain biking (or long granite slabs) for rest days.
Another good option is the Austrian Tyrol. Zillertal, Schleirwasserfall, Chinesisiche Mauer. There's an excellent Tyrol sport climbing guidebook available. Again, lots of good mountain biking too.
A place I never managed to get to due to buggering up my ankle at the start of the trip, was the Picos de Europa and Costa de Verde area in Northwest Spain. There's a new guidebook just out to the area which looks like a superb summer venue.