It's easy to forget about an entry once it slips off the front page of your blog, but it doesn't mean the entry will be forgotten. Remember, visitors may find the page through a search engine search or a backlink from another website. Instead of hoping the content will remain forever fresh for anyone who comes across it, periodically go through your archives and dust them off.
Start with your webstats and referrer logs. See what keywords people are using to find your website, check the search engine to see which page on your site the results lead to, and do an inventory of the page. Update any egregious errors, add links to other relevant blog entries, and anything else you feel may add to the value of the page. Also, check to see which pages people are linking to from other sites and make the same changes.
Once you've updated the pages that are in the spotlight, try perusing your archives starting with the oldest and work your way to the present. You may find articles that you previously published that may spark some inspiration for future blog entries or opportunities to update some of the old entries.
This is also a good opportunity to check your links out to other sites and update the ones that no longer work. Make a small note at the end of the entry letting your visitors know when and what was updated (this is optional, but polite).
Archive, Management, Organization