I switched from phpNuke (including phpBB2) to joomla! and Fireboard and needed a PMS solution. As far as I remember I could only find JIM as a non-commercial component that really works.

I give 4 stars 'cause when I set the appeareance to Tabs instead of Buttons it shows nothing but the tabs itself under IE. This might be due to my template, I don't know.
On the other hand those tabs are quite eeer....
So you'd better go with the Button setting.

Also I missed the popup alert function but I recently found barasax's hack which I will test. If that works I will be more than happy with JIM!

All in all this is a very good component IMO. JIM is not fancy, not loaded with a lot of unnecessary features BUT does the job. Easy to install, simple to use even for joomla!-noobs.
That's all, recommended!

I used this brilliant extension to rename my nuke tables in my joomla db.
I was on converting a phpbb forum which was part of a nuke-powered site. I copied all the nuke tables in my joomla db. As I am not familiar with mysql I couldn't replace the nuke_bb* "prefix" on the nuke tables in a batch process. Also I did not want to do it manually (more then 100 tables...).
This extension did the job perfectly in a mouseclick, many thanks for the developer!

Recommended

I needed a tool that makes possible for my registered users to attend events (AE calls them sessions). This extension does the job.
However it would be even better with some additional feature. My most wanted is:
-Front-end access for registered users to submit their own sessions.

Thanks for the developer team for that great component!