Firefly's Beetroot is a regression tester designed with ease of use in mind.
The only requirement to operate it is some basic knowledge of the UNIX shell.
Note that this is not a unit test framework.
Testing occurs at program granularity, not at a level of a function.
This is meant to be used only with software with a stable user interface.
Changes in the interface could break your tests. Be warned.
The Winfessor .NET Unit Test Library is a very simple, feature-lacking unit test framework and Winforms GUI designed to get the job done. Tests are ran on a background thread so the GUI remains responsive. Attributes are used to designate test items.