There's some great high-tech, hacker, and startup stuff going on in Saint Louis:

Yearly

The Strange Loop Conference: https://thestrangeloop.com/

Monthly

Lambda Lounge: http://lambdalounge.org/

Saint Louis JavaScript Meetup (STLJS): http://www.stljs.org/ http://vimeo.com/stljs

STLRuby: http://stlruby.org

Code Until Dawn: http://www.meetup.com/allnightlong/

StartLouis: http://startlouis.com/

Build Guild in St. Louis: http://saintlouis.buildguild.org/

There's lots more too, those are just ones I'm either involved in or hear about frequently.