The aim of the ALENEX workshop is to provide a forum for presentation of original research in the implementation and experimental evaluation of algorithms and data structures.If you use Google Calendar, click to add the deadline to your calendar.
Another deadline that's coming up even sooner is for the Fall Workshop on Computational Geometry, the annual math-conference-style event for geometers. This year it's in Smith College on Nov 10-11, and is being run by Ileana Streinu. One of the special events this year is a 3D Printing demo by Joe O'Rourke. The deadline is Sep 22, and it should already be in your calendar by now, but if not, click here .
p.s if you want to create buttons like above for your event, here's the link.