Try
Portedmods
They have one over there that will put in a drop down menu, which allows you to select from a list ranging one day to a year. It lists all the threads started within your the specified time.
Or were you talking about the at a glance mod that is on this site. I believe you can get that at ported mods as well.
If you are talking about the forum block on the front page it is included with the theme packs.
Linear Mode
