The obvious one is Nessebar, only 1 Lev or on on the bus. Other places would be Sozopol, a nice place just down the coast a bit, usually sold by reps as part of the Ropotamo River excursion, which some like & some don't; The Blue Mouintains, which is OK, but watch the included visit to a crystal factory - the prices are a bit high, there is a lovely crystal shop in Nessebar which is much cheaper, and they will pack your purchase for the flight home, at no charge. There are numerous variations on the boat trip excursions, just pick what you want, and the ubiquitous jeep safari. Bourgas isn't bad, either for a change, and you can even visit Istanbul!. I'm sure there will be lots of others on here with their lists, there are actually quite a few trips to do