In terms of tasks it is very important that they be time limited and age appropriate. So for example:
Coordinate information architecture updates for joomla.org redesign project
I replaced with a specific assignment to write one article. Remember among other things students can only work on one task at a time. That means you can't give them something that is potentially 6 months long. In general challenging projects might take a month, intermediate projects a week or two. Also, as much as possible please have a specific work product in mind. Any task that is in the final group must have a specific work product and evaluation standards (so we can say the work is acceptable or not).
This is too general. Please name a specific task or set of tasks.