The nuget feed was broken (think it was credentials, but the server could have been down too). The deploy step hung at the following step for at least 30 mins before we cancelled it:
2012-03-12 00:49:57 INFO Downloading NuGet package 3.638.0.0 from feed: 'http://teamcity:88/httpAuth/app/nuget/v1/FeedService.svc’
2012-03-12 00:49:57 DEBUG Finding package (attempt 1 of 5)