I never really checked before to see how often Google crawled my main website, but just looking now I see it was last in Google's cache on May 24, 2006. It's a static site, but has had many small updates in the last 6 or 7 weeks, and a major redesign in the last three weeks at which time I also submitted to DMOZ.
Other static, and otherwise unchanged (never updated) websites I've made have been cached by Google in the last week, or at worst, the last 2 or 3 weeks. Should I be worried about my main site? I can't think of anything bad I've done that would get it banned, other than maybe some poor quality incoming links which have been there for almost one year (I know better now, that was then, this is now).
So, should I be worried? Anything I can do to get Google to crawl my site again?