I agree with a lot of good suggestions given by others; especially treelike's question about whether your kids want high-energy activities. Here are some ideas:
-- The book Sleep Thieves argues that 8 hours of sleep per night is less than the optimal amount.
-- Lie down for a rest at lunchbreak.
-- Meditate, e.g. for one minute per day during breaktime
-- From time to time during the workday, take a few deep breaths, stretch your muscles, get in touch with your emotions, and ask yourself what's causing you stress; then get those issues clarified, into your GTD system and out of your head.
-- Improve thyroid function: e.g. avoid drinking fluoridated water; maybe increase your iodine intake.
-- Maybe it's better to listen to your body and rest when it tells you to, than to try to quickly energize yourself.
-- Splash cold water on yourself to quickly energize.
-- Have everybody in the family collect or invent jokes during the day each day. Share them when you get home, and laugh good loud healthy laughs to release tension.
-- Laugh for no reason, as in Laughter Yoga, together with your family. http://en.wikipedia.org/wiki/Laughter_Yoga
-- Read the comics together when you get home.
-- Experiment with various activities to see what you can do with the family that's restful for you. Everybody lie down for a nap together? Dance to slow music without talking? Do yoga? Play a card game? Read the comics together?
-- Play games like Ring Around the Rosie and laugh a lot.
-- Give each family member including yourself 3 minutes to talk about how their day went, without being interrupted.
-- Have each family member list 5 things they appreciate (e.g. good things that happened that day like having stopped and smelled a nice flower on the way home).
-- Use a method of commuting home from work that reduces stress, e.g. walk, jog, bicycle, take a bus and close your eyes during the ride.
-- Read "You Don't Have to Go Home from Work Exhausted" by Anne McGee-Cooper http://www.amazon.ca/books/dp/0553370618
-- Reduce your hours of work. When my kids were little, for a year I worked 80% of full-time hours and it was great. I got to go home about 3PM every day and I still had both time and energy and could take the kids to a museum or something.
-- Arrange to do your last hour or two of work at home after the kids go to bed (but make sure you get enough sleep).
-- Use "Game for Active Child" http://web.ncf.ca/an588/par_game.txt to get your child(ren) to have fun while you don't have to exert much physical energy
I recently ran across a book called "Fried: Why You Burn Out and How to Revive" by Joan Borysenko. I've not yet read this one, but have read some others by Joan and loved them.