Problets are little coding problems that are designed to be useful for learning by beginning programmers. Typically teachers use small examples and exercises to help students internalize concepts like arithmetic expressions. Students are asked to evaluate expressions, usually on paper, and write out the results.
The problems with this are that it is very time consuming to create these exercises and even more time to evaluate, check and grade each student's work. The Problets site automates this whole process.
Problets can be generated with different problems for different students. Teachers can sign up to use this site and get graded results for the students in their classes. IT looks like quite an interesting site.
The Problets available at this site are available in C++. Java and C#. I wish they had some in Visual Basic as well. Still they are useful for people teaching the programming languages they are available for.