Greasemonkey Script Nests Threaded Discussions In Twitter Pages
Pratham Kumar genned up a greasemonkey script, Nested Twitter Replies, that tries to nest Twitter discussions, and does so right in Twitter pages.

Twitter, originally uploaded by Stowe Boyd.
I tried using Tweetree for this functionality (see Tweetree: A Better UX For Twitter(, but it is annoying to have to use a completely different site for just one feature.
This script is so good that I find myself actually looking at my Twitter page again, instead of using Tweetdeck. Maybe Tweetdeck will do this someday?