Went out to dinner at a brewpub last night. We were a table of 4 adults in our late-20's and early 30's. A little while after sitting the restaurant's "official magician" came over and performed some tricks for us at our table. When he was done he told us he accpeted tips. We enjoyed his show and were entertained by him so we scrounged around and gave him a few bucks (basically all of the singles that we had between us). We had no idea what an appropriate tip was (we hadnt even ordered yet so a portion of our food bill wasnt an option nor am i sure if that makes sense). Any ideas what is expected in this case?