To a Protestant, the trappings of Orthodox worship can look very Roman Catholic. This short booklet clearly and concisely explains the fundamental differences in the outward similarities.
I'd recommend it to anyone trying to explain to Protestant friends and family (especially ex-Catholic friends and family) how the Orthodox church is not the same as the Roman Catholic church. I wouldn't necessarily recommend it for your currently Catholic friends and family, since it is written by an Orthodox priest who converted from Roman Catholicism, and he presents the flaws he found in RC theology and practice.