Displaying all posts regardless of date – Ultimate Tag Warrior

I am attempting to use UTW to further classify posts for EventPress, a WP-based script i’m working on. The problem is WP’s default method of display posts, is only those less than the $now variable. I would like to have this functionality remain intact, and add in something that would detect if either ?tag= or /tag/ are present, and if so, to display all posts, regardless of date.

Another route, if easier, could be to copy over /index.php to /tag.php and set the now value to one year in the future.

I know enough PHP to be dangerous, but not enough to successfully do the above. If anyone could give me a pointer as to what direction to head in/how to start it would be greatly appriciated.