Recommended optics for experimentation / hobbyist.

What optics would the Guru's recommend I start acquiring?

I already have 5 kinematic mirror / optics mounts on the way which I found on ebay from various vendors.

I also have 12 first surface mirrors on the way from a local vendor that were quite cheap.

Finally, I have some various optics from a LCD projector I scrapped and pulled the optics out of (Combining cube, FS mirrors, 3-4 Lenses of various focal lengths).

As with other hobbies - I'm assuming there is a general "grab bag" of items that get used a lot in various experiments, etc.

The things I have found from reading here which may be useful are:
Diffraction grating
Spatial Filter
Dichro's

I'm also interested in any laser based experiments that can be conducted, if folks could post some interesting things they have done with their lasers at home.

The floor is yours..

For optics you can go to surplusshed.com. It's a very nice website, I just hope not everybody buys the store empty

I'm also looking for laser experiment, this is a part of my todo list:

• Resolving the individual lines on a CD, preferably with the pits visible. Quite difficult.
• Measuring the light speed by measuring the time it takes before light gets back.
• Building a N2 laser
• Making a 3 mirror HeNe laser (read on sams laserfaq, can be used to get different colors out of a HeNe).
• Build a monochromator or spectrometer.
• Build a scanning fabry perot interferometer, or any other inteferometer like a michelson or mach zehnder.
• Measuring the coherence length of different light sources
• stabilizing a HeNe laser in power and frequency