It depends on what you want to do. Have you looked at the questionnair or the choice plugins? They both allow submissions of answers to user defined questions.
You could also go the route of a custom block if you need a particular level of control over the display of a set of questions-- this isn't too hard if your question/answer format is simple and doesn't require the complexities of the quiz question types, gradebook, etc.
We did this for some learner-specific survey style information (ie it related to the learner, not the course), and then we wrote reports to pull out the aggregate responses by class groups. The moodle block development tutorial is quite good, and goes into detail about using moodleforms and storing the information in custom tables for the block.
You might also look at LTI; you can write the sort of activity you want outside of moodle, and set up a 2 way communication between moodle and your activity.