When we create a blog or a wiki for students, our aim is to help them learn outside the classroom and become more independent in learning: we add useful links to practice grammar, consult a dictionary, improve skills. Students do the assignments and then they look for some online fun.
I think it is a good idea to offer some fun activities that in students' eyes don't look like lessons, but being in English and appropriate for their age and level, help them improve their English without noticing it.
These are some fun activities I offered on a class wiki:
Free Rice – you play a vocabulary game and for every answer you get right, ten grains of rice are donated to help end hunger. It is easy to add their banner to spread the word about the programme and allow the students an easy access.
Draw a Stickman! – you draw a character who interacts with you to help you tell his story.
Build Your Wild Self – Animal lovers can add some animal parts to their human portrait and learn about the animals in the process.
I mentioned the fun page to the students. Now I listen carefully to their comments and add a new activity from time to time.