Set your brain to fluff: This week's spate of DVD releases just won't be stimulating your gray matter. If you've gone back to school after Labor Day, then this week's releases will be a welcome relief from the intellectual grind. If you're a working stiff, slide into your favorite easy chair after a hard day's work and relax. First up there's 'Prince of Persia: The Sands of Time,' a fast-paced action-adventure that harks back to the swashbuckling adventures of yore. Follow that up with two comedies for your romantic enjoyment: 'Letters to Juliet,' a lovelorn column come to life, and 'Just Wright,' a sports-related romance set against the action of the NBA. If you want more rigorous mental jolts, check out this week's Blu-ray entries: 'One Flew Over the Cuckoo's Nest,' 'Breathless' and 'Se7en.'