According to at least one source, the custom of playing dreidel was actually started in the time of the Maccabis. They say that in an effort to circumvent the Greek decree against studying the Torah, children and their teacher would have a dreidel handy to start playing in case the Greeks came upon them studying the Torah. They would claim they were not studying instead they were just playing dreidel.
Despite all of these explanations, in truth, dreidel is not Jewish in origin. Rather, dreidel is really the rather old game of teetotum. Teetotum, which uses a top with four sides and four letters is one and the same with dreidel. The letters that appear on the dreidel are really just the Hebrew letters that appear on a German or Yiddish teetotum, G, H, N, S. G= ganz (all), H halb (half), N nischt (nothing) and S schict (put). Teetotum dates back to at least the 16th century long before we have any Jewish allusions to dreidel (it was originally totum or top, but became TEEtotum due to the use of T for take all, on the top). The well-known depiction of children’s games done by Brueghel in 16th century includes Teetotum(see here and here for the complete painting). The earliest Jewish mention of dreidel or the significance of it dates to the late 18th century.
The story connecting dreidel to the ruse of the Maccabis was first published in the book Minhagi Yeshurun, which was first published in 1890 (the name was changed to Otzar Kol Minhagi Yeshurin in the third edition, which is available online here from Hebrewbooks.org. The author included a nice picture of himself at the beginning, although he was a Rabbi in Pittsburgh at the turn of the twentieth century, he is holding a quill pen.) His source is a contemporary of his. [As an aside, although his explanation of dreidel is well-known, he offers a similar explanation for playing cards on Chanukah, i.e. that the Maccabis did so. However, that one is not nearly as well known.]
Dan Rabinowitz, “Chanukah Customs and Sources”, The Seforim Blog (25 December 2005) [http://seforim.blogspot.com/2005/12/chanukah-customs-and-sources.html]