In May 2007, after obtaining a DMK FireWire camera, I had the idea to observe exoplanet transits with my limited equipment (see below). After reading papers, some test and calculations, I came to the conclusion that this could indeed be possible with the brightest transit stars and the deepest minima. I chose HD 189733 for this purpose and developed IDL code for the light curve analysis. My first observation was on 2007-06-07. And it was a success! I could not quite believe it - but subsequent observations confirmed the reliability of my methodology. Unfortunately, the weather here prevents me from observing exoplanet transits more often...
This is the equiment used: Takahashi FS 60C, DMK 31AF03.AS
So all it took was a 6 cm refractor and an uncooled 8-bit camera. I even did not have any guide control. But, some sophisticated data analysis revealed the dimming of the host star HD 189733.
For details, have a look at this PDF of a presentation I gave at the ESOP 2008 conference.
Michael Theusner, http://www.theusner.eu
You can read the full article of Michael here.