Is anyone a member of the Institution of Mechanical Engineers? I'm not, but I used to attend some of their local events, especially those related to energy. I used to think they were quite good. What's more, there was free coffee and sandwiches.
Negativeness, but I am a member of the British Computer Society (so my yearly fees do pay for some sandwiches). The IET and IMechE are better IMO, the the BCS sometimes does a good event too. They seem to go through phases of putting on interesting lectures, then running out of steam.
I sometimes wonder why I stick with the BCS. I can put MBCS after my name, but apart from that, the IET seems much better. I signed up to attend a lecture titled "Kinect: you are the controller", which is about Microsoft's Kinect for XBox 360. I've no real interest in gaming any more, but I thought it would be good to attend another BCS event. Then I noticed it was an IET event.