You'll have to search for them, but you can download five PlayStation Vita games through the PS3's PlayStation Store. The selection of early, hidden releases includes Uncharted: Golden Abyss (which is not discounted at all at $49.99), Hot Shots Golf: World Invitational for $35.99, Wipeout 2048 for $35.99, ModNation Racers Road Trip for $26.99, and the PSN-only Super Stardust Delta for $9.99.
Sure, you probably don't have a Vita yet, but don't let that stop you from building up a library. Then, when the system does arrive (or if you have one right now!) you can use the Content Manager Assistant to transfer the games to that huge memory card you'd better buy.