i don't know if it should necessarily be 'fun'. like not everything is fun. however it should be inspiring, like it's a challenge, and may frustrate the hell out of you, but you want to do it, and want to learn more. you should be learning something. teaching everything so it's fun might not get the students learning much. like we had a lecturer for ed psych last week, and he was funny and stuff, but i personally learnt bugger all (perhaps because the topic had bugger all in it!). eg. i don't believe bribing makes something fun, the kid just wants the food, but that doesn't mean they care or are learning anything productive.