recreational maths venue for amateur mathematicians

The Best I know is G4G (Gathering for Gardner Foundation: http://gathering4gardner.org). From 2010, people around the world celebrate the birthday of Gardner and G4G somehow links all of them together. It is up to you at what level you celebrate it. We did it at our own university and students from all departments (science including mathematics, physics, chemistry, and social science) were involved. Just visit G4G and you get many useful ideas and you may share your own ideas.

Recreational Mathematics Colloquium mentioned in the comments above : http://ludicum.org/ev/rm/13

A mixed bag of (possibly) relevant journals, some of them well-known:

• Convergence
• Forum Geometricorum
• Mathematical Intelligencer
• Mathematics Magazine: MAA JSTOR
• Plus

EDIT

And more, including a French one:

• The Mathematical Gazette (UK).
• l'Ouvert (not sure about its current status, the site appears not uptodate and somewhat broken)