EDSITEment! has lesson plans on a variety of topics, sorted by ages and categories. There are ones on Pompeii, Latin, and other topics from the ancient world. Each is clearly set out with lists of resources. There are also plans in other subjects, which can be very useful if you are assigned a last minute class in a different subject.
Teaching Latin to the Young
With young students, even more than with older students, you need to think about what your goals in teaching the class are. A Latin class