Upgraded both my blog and our Family Twitter blog to the latest WordPress release which is version 2.6.
I immediately had a problem with a plugin (WP-DowloadManager from GamerZ). After going to the plugin site which had a discussion forum, they had already found out that WP 2.6 is now using the same function name as the plugin hence the error. Of course the developer is just awesome (as are all of his plugins) and he had a quick beta fix right away.
The WordPress community is really fantastic.