Gamerush has a stackable deal that beats this EB offer.
$20 off new PSP titles for two game trade-ins. Trade in three, get $5 extra for each game. I traded in The Sims(for GC, don't ask...), Beach Spikers, and Freedom Fighters, and got Twisted Metal: Head On and $5 extra in store credit.
Like EB, Blockbuster will soon realize they're getting the poo end of the stick. Jump on it now. Details here:
shit I had some of those and traded them in prior dammit. How'd you find out they stopped the deal early? That sucks..there goes my nearly free Wipeout Pure.