I'm looking for a simple and light tool for tracking ideas and bugs for small physics lab team (4 members). Bugzilla and Trac have too much fields and other stuff for us. I don’t think that we need more than issue descriptions and simple categorization. But we are not happy with text and excel files suggested here. Could you please advise me anything easy to install preferably?
Mantis is really lightweight has lots of community support and is easy to use and configure.
If you have a php web server and any major database, just copy the files to the an arbitrary web dir and run the web based configuration. Otherwise just download xampp, and install there.
I'm very happy with Ruby-based Redmine. It's not really less complex than Trac, but it's faster and easier to use IMO, and more configurable. Try the demo, maybe you can cut it down to the minimalistic level you want.
As for easy installation, the Bitnami Redmine stack offers a Windows installer and a Linux Virtual Machine - extremely easy to set up.
I'm curious to know why you ruled out Trac; I've always considered it to be lightweight. Although it has a couple more fields than you requested, you're free to ignore fields that you don't care about. The rest of Trac's features can be ignored (wiki, roadmap) or are worth having since they're basically free (timeline, version control integration).
You asked specifically for something easy to install; the easiest installation would be to take a virtual appliance (from someone like TurnKey Linux, JumpBox, or the VMware Virtual Appliance Marketplace) and run it within a VM.
I like a commercial tracker called Gemini. They used to have a free 5-user license, but it looks like it's been dropped to 3 users. Not useful for your team (of 4 members), but may be useful to someone else reading this thread. It's based on ASP.NET with SQL Server back end.
As with others that have been mentioned, Gemini can be less of a "lightweight" solution, but the out-of-the-box configuration is usually enough to get your project started.
Have a look at Versioned Artifacts - basically it adds categorization and usability to plain text files.
Lighthouse is a good online bug tracker. It has a deliberately simple design that focuses on the essential stuff without too many extra fields and options.
Its pretty cheap or they have a free option for small projects, I think. Its definitely free for open-source projects.
I think my bug tracker, BugNotes, fits the description pretty well!
For such a small team email could be the easiest way then. You can also check out our personal productivity tool that helps you manage project related email: http://yoxel.com/personal-commitment-manager.html