The OpenForce Event happens once a year at the Mandalay Bay in Las Vegas. There is also a companion event several weeks earlier in Europe. If you have never attended, I would highly encourage you to attend at least one. Not only are there 4-5 days of DotNetNuke at the Vegas event, you may also attend any of the many DevConnection sessions of Asp.Net Connections, VisualStudio.Net Connections, Architect Connections, and SQL Server Connections.