LinkedIn launched the LinkedIn Events module: Announcing LinkedIn Events. You get event recommendations, you can indicate if you are going and you can see who else is going. Once you mark an event, it shows up on your LinkedIn profile.
This is a great feature, but not a new idea. I have been a fan of Upcoming for while: [Doug on Upcoming]. The site is classic example of Metcalfe's law. It gets more useful as more people use it.
LinkedIn provides a bigger user base of connections to tie into. I have 323 "connections" on LinkedIn, but only 23 "friends" in Upcoming.
Upcoming is a more open platform. In particular, Upcoming supplies lots of RSS feeds giving you notifications of new events that your "friends" are attending and new events added to groups that you join. It also ties into Facebook and other aggregators like FriendFeed.
With all these new applications, LinkedIn is starting to move closer to the Facebook model of aggregating information. It will interesting to see how the events and other application features evolve.