Inspired by Scott Hanselman and his relation from Visual Studio 2008 InstallFest in Portland Polish user groups started the series of events in Poland. First such event was organized by Szymon Kobalczyk in Kraków and you can read about it on his blog. I was one of the organizers of the event so I cannot tell I liked it because I loved it. It was a huge fun for me. I believe it was a great success.
At the moment there was a second InstallFest in Wrocław. I was there, and I think it was also well organized. We had a 'What's new in VS 2008 and .NET 3.5' and 'Visual Studio Extensibility' lectures. After that there was a contest - whit a set of questions concerning VS and .NET 3.5. Even I won something: Resharper licence (I created an extension method that multiplied int). We also played Counter Strike and had a powerball contest (one of my friends won this one with 11 300 swings per second). I had a great time there. Great thanks to Łukasz Olbromski from the .NET User Group in Wrocław.
You can find info about the InstallFest in Wrocław on Chris Koenig blog and Tadeusz Golonka (Polish Regional Director) blog: Visual Studio 2008 InstallFest we Wrocławiu (blog in Polish language)
I know that other .NET user groups in Poland host the event also. The next one will be in Gdańsk (http://www.codeguru.pl/fullnews-2685.aspx - also in Polish language) and another 3 or 4 user groups is organizing them at the moment.
We also plan to start SQL Server 2008 InstallFest around .NET and SQL user groups in Poland. It looks like this kind of event is a hit here. It is something we missed for some time in user groups organization. I believe it's just a beginning.