cardboard boxes, tunnels and old phone books are all good. plastic slinkies are a hit with most rabbits. anything they can toss around is good, like baby keys.
as a note, those edible logs aren't very healthy and they're a no-no with any bunny that has had GI stasis issues in the past... but I, too, keep one around because if they don't have their precious log, they chew through the coroplast in their condo and I figure eating a junk food log is better than eating plastic. sometimes you've just gotta go with the lesser evil if it stops them from eating their own home, lol.