All of Japan’s universities and some of its colleges hold gakusai, or students’ festivals, every year in autumn. Most of the after school circles and clubs do presentations (dance and singing performances, poetry recitals, live drawing etc) or have a stand and sell typical Japanese street food, such as ‘okonomiyaki’ (savoury pancake), crepes and much more. If it’s on offer, try my favourite: fried ice! 
Image courtesy of miyatadental.com
Some cool ones to visit, with their 2014 dates:
Keio University’s ‘Mita sai’
21-24 November 2014
Visited by some 200.000 people each year, one of the bigger festivals. Enjoy food stalls, recitals, dressed-up people watching, and their impressive dance performance (I participated in it once!).
Sofia University’s ‘Sofia Festival’
1-3 November 2014
This year’s theme: travel. Join Sofia’s students in the festival they’ve worked a year for to produce. With so many food stalls and performances, I’m sure you will not be bored!
http://www.sophia-festival.com/
Image courtesy of blog.livedoor.jp
Kyoto University Festival
21-24 November 2014
Also here you can find numerous festival food stalls, performances and club activities. If you’re lucky you might meet some cross dressing members of the anime club!
http://nf.la/ 
Image courtesy of blog.livedoor.jp