Hi Bonnie,
I have just installed Hot Question and have it working in one of my Moodle 2.5 dev sites...but there are some gotchas. The version in Moodle plugins is for Moodle 2.0 and 2.1. It will work in 2.5 and probably 2.4, but has three or four things that need to be fixed by the developer.
One of the problems (addinstance) got fixed three weeks ago in the version that is available via github, which is still really for 2.0/2.1. (https://github.com/hit-moodle/moodle-mod_hotquestion) One problem, for everyone (admin, teacher, student) is that when you are in the module, clicks on Administration links do not seem to work. Have to click something in the Navigation block or something on the breadcrumb bar to get out of it.
If you try it, and you keep debug reporting set to Normal, your users should not see any problems report by debug...at least that is my experience on the development site I have it on.
As it is right now, I would not recommend using it on a production Moodle 2.4 site, UNLESS, you are running your own, small, Moodle site like I do, and do regular backups. That way, if I have a problem with it, I can readily dump it and its tables from the db, or restore to a backup, and then be back in business. I do not use the module right now as the way my courses are structured now, I don't need this type of capability.
If I get the chance to put in a bug report on all the problems I have found, in the next day or two, maybe the developer can get them fixed soon. (I am playing hooky right now...should be grading some essays)
If I haven't scared you off completely and you would like to try it on my dev site, let me know.
AL
PS: Just put the github version on my Moodle 2.4.3+ dev site. Works exactly the same as it does on my 2.5 dev site.