This one's for foodies and artsies alike. The Jiman-ichi festival, now into its fourth year, brings together culinary and craft specialities from across the country, meaning that (last year, at least) visitors had the chance to try shimanto udon from Kochi-ken, shirasu-don from Kanagawa, and even Okinawan noodles, all without having to travel any further than Harajuku. This year's menu has yet to be decided, but it's never overpriced in the way that other festivals of this nature tend to be (we're looking at you, Oktoberfest), though, with the stalls numbering over 40, there'll be enough cheap tidbits to ultimately break the bank. Fortify your wallet accordingly.
Also worth noting: Jiman-ichi takes place alongside Super Yosakoi, making this the ultimate Japanese traditional day out.