The Trinity Mathematical Society - Society intended principally for members of Trinity College Cambridge, with the aim to promote the discussion of subjects of mathematical interest. Includes events calendar, membership information, and talks archive. - http://www.srcf.ucam.org/tms/
The Archimedeans - Cambridge University Mathematical Society, open to anyone in Cambridge with an interest in mathematics. Meetings, member services and lecture notes. - http://www.archim.org.uk/
Windsor Mathematics - Records of results achieved by the mathematics enthusiasts of Windsor, Ontario, Canada. - http://www.windsormath.ca/
Chaosoc - Student maths society at the University of St Andrews, Scotland. Upcoming events and course guide. - http://www.st-andrews.ac.uk/~chaosoc/
Pi Mu Epsilon - Honorary national mathematics society promoting scholarly activity in mathematics. Includes links to chapter websites and membership information. - http://www.pme-math.org/
UAH Math Club - University of Alabama at Huntsville. Puzzles and talks. - http://www.math.uah.edu/mathclub/
DePaul Math Club - Meetings, committee, links. - http://mathclub.depaul.edu
Mu Alpha Theta - Mathematics honors society high school and junior and community college students in the US. - http://www.mualphatheta.org/
College Math Clubs - A list maintained by the American Mathematical Society. - http://www.ams.org/employment/club-sites.html
UBC Mathclub - University of British Columbia. Information, exams, books, meetings, sports, photographs. - http://www.ugrad.math.ubc.ca/~mathclub/
Student Society of Financial Modelling - AGH University of Science and Technology, Cracow, Poland. Monthly meetings in cooperation with the PRMIA Chapter in Crakow. - http://www.knmf.agh.edu.pl/
Radical Pi - Ohio State University Math Club. Calendar, resources. - http://www.math.ohio-state.edu/undergraduate/radicalpi/
Oakland University's Math Club - SAM - Students for the advancement of mathematics. Hosts events and meetings. Includes recent news and fun links. - http://www.oakland.edu/org/sam/
University of Warwick Mathematics - SSLC - Student and Staff Liasson Committee. To improve communication between students and teachers about courses being taught. Includes minutes and agenda of meetings. - http://www.maths.warwick.ac.uk/~msslc
ASUM Club - Academic and Social Undergraduate Mathematics at New York University. Events, resources and links. - http://www.math.nyu.edu/~apa211/mathclub/frames_index.html
Euclidean Mathematics Club - Murray State University club. Events, news and links. - http://campus.murraystate.edu/org/math/
University of Waterloo PMC - Pure Math, Applied Math, and Combinatorics and Optimization Club. Books, events and links. - http://www.student.math.uwaterloo.ca/~pmclub/
University College Dublin Mathematical Society - Stimulates interest in mathematics, mathematical physics and its many applications by organizing fortnightly talks and social events. - http://www.ucd.ie/~mathsoc/
Mu Sigma Rho - US National Statistics Honorary Society. - http://www.stat.sc.edu/msrnatl.html
Australian Mathematics Trust - Non-profit organisation which administers 'mathematical enrichment' activities for Australian and international students. Information on activities and publications. - http://www.amt.canberra.edu.au/
Harvard Math Club - Information on club activities and for undergraduates concentrating on (or even just interested in) mathematics. - http://www.math.harvard.edu/~mathclub/