Send you child(ren) themed lunches...Pick a different theme for about 8 days or so and rotate them...
one them can be the tired old meat, cheese and crackers...but livenit up some...use wheat thins or triscuits, or something similar for the crackers, use pre-cooked ham chunks for the meat and string cheese for (or other snack cheeses) for the cheese...
Do a fresh fuit kabob and dip day...the dip is peanut butter...the fresh fruit is arrayed on skewer, use apples, pinapple chucks, berries, melon, bananas, grapes, etc...whatever is in season. Help them get their vegetable in by sending V8 fruit fusion (make sure it's one with 100% juice - not all are) for their drink...
Do a build your own pizza day...send pre-toasted english muffins, some grated cheese, olives, pepperoni and other fun toppings...put the pizza sauce in something they can access easily and then toss..
Do a veggie day...give them carrots, celery with peanut butter, radishes, broccoli and cauliflower...for dip, send something like honey mustard or other non-dairy fun dip for veggies..send good ol' 100% fruit juice with it for their fruit serving for the day..
For a chicken nugget day, you can send barbecue sauce for dip and some pre-cooked chicken nuggets...or, you can send the lunchables version...
Send them peanut butter and jelly sandwiches but surprise them with a bit of candy or dried fruit in the middle...Use frozen waffles (they can be bought in multigrain and fruit variety for extra nutrition and fun) for the bread, or frozen pancakes...(cook them before you make the sanwich and put them in a sandwich baggie)...
That's all I can think of for now...I am sure there are others...but this should get you started...Just remember to keep it fun and each time you make any of these you can vary them up a little...
Good Luck!!! ;-)