Fake iPod touch lockscreen?

So I have two annoying syblings and pardon my spelling I'm doing this on my itouch, and they always try to use my iPod but they never get past the lockscreen. I ended up waiting 1/2 an hour to type the pword but then I just synced it with iTunes. My question is is there any apps from cydnia that show a fake lockscreen or a black screen and on order to unlock it you have to press a certain spot or something that makes it look like my iPod is not working. Thanks. FYI 2nd ten itouch 2.2.