Someone on the LDHEN jiscmail just asked about short tasks for putting in our VLEs that are designed to promote student learning. Personally I am not keen on multiple choice or drag and drop tests. I think they lead to convergent thinking and the notion that there Is, ONE right answer to every problem... and so forth (do see Ken Robinson's animated talk: Education - a paradigm shift:http://www.youtube.com/watch?v=zDZFcDGpL4U).
To promote active learning with 'my' students, I've become increasingly keen on short weekly writing exercises that can happen either live in class - or be given as an on-line task that is set and submitted via the VLE. These can be semi-structured, along the lines of: 'Summarise what you have learned from today's session and discuss how you will make use of that in your final assignment...' to really quite shaped and formulated writing exercises. If anyone in the blogoshphere is interested, I can send you a module seminar handbook that has a range of different weekly writing tasks that we used with a second year group - though this formulation tends to work at every level.
We found that students who participated in the tasks got the best marks they'd ever received for their final pieces of academic writing, that they felt they had more knowledge about the course content, that they'd felt able to be more creative on the course - and that they finally understood why they were reading.
If doing this with small groups, it would be possible to give feedback on the writing submitted. With larger groups some form of peer review could be facilitated...
To increase participation, you always have the option to incentivise by awarding marks for submission (1 mark per submission up to a maximum of ten, say) - or even allowing the submission of a revised formulation of the written submissions as a patchwork text for the final assignment.