Three Card Tonk is a card game played with a standard 52-card deck that I learned decades ago in Michigan. It is normally played by several people rather than the two we are limited to with this program (you against the computer program), but the only real difference is in strategy, not the rules.
You should consult the rules for 3-Card Tonk even if you are familiar with this game, because the rules also describe how to interact with the applet.
This game is significantly different from the five card version generally known simply as Tonk. A search turns up several sites with rules for that game, and also shareware programs, but I know of nothing out there on the web about this game.
This program is the Java successor to a FORTRAN program written in 1971. I have a separate page on the history of this program and some of the differences between the old TTY version and one based on a graphical interface. The only important detail is that I have left the heuristics unchanged so the computer's playing style has not changed from the original program.
The applet will just barely fit in a 640x480 display, and will fit best on smaller screens if you hide some of the browser's menu bars that take up space across the top of the display.
For reference, the "card table" should look something like the screen capture shown below of the output produced by Sun's JDK appletviewer. If it does not, your browser's Java Virtual Machine must be buggy in how it handles the colors specified here; most of the problems I have seen were with the buttons. In any case, I would be interested in knowing what browser version you are using if it does not work properly.
Other info on this, my testing procedures, and other possible problems along with contact information is on a separate page.