Firefox with the Greasemonkey extension: You're cruising through your unread items in Google Reader, and suddenly you want to mark all the items AFTER your current one as read, or BEFORE your current one as read—but not all of them. The Mark Until Current As Read Greasemonkey user script can do just that. With it installed, press Ctrl+Y to mark items before the one you're looking at as read, and Ctrl+I to mark items after as read—a nice feature for power GReader users. The Mark Until Current As Read user script is a free download, works with Firefox and the Greasemonkey extension, and is currently on deck to be included in the Better GReader extension. Thanks, CliffordBadger!