Will this change your life? No. But will it make your LJ experience that much more thrilling and meaningful? Also no, probably. But it's kinda nifty, and apparently lj_nifty-worth.
PS. If you happen to know how to make LJ display the links, let me know.
PPS. LJump! and LJoo? are subject to the Creative Commons license. Basically, spread it around but don't say it's yours. I'd prefer if you linked to this post rather than posting it in your own journal, but whatever floats your boat.