Travel both the country and as much of the world as I could afford.
Visit all the friends that I don't see very often.
Make a real effort to read all those books I havent yet read.
My grandfather used to say: there are two types of people in the world: those who simply take trips (even if to other countries) and then those who travel (and take in the experience and, hence, grow).
Here's a possible itinerary for you:
Arrive at Guatemala City
Take a 40 min ride to Antigua, a beautiful place. Stay in Antigüa as your HQ.
On day one, explore Antigua, drink the coffee and eat chocolates.
Day two: hike a volcano, called Fuego
Day three: visit a coffee plantation
Day four: go to lake Atitlán and stay in San Marcos for several days. Take in the local festivities as there is always something being celebrated.
Day five: travel by boat in the lake to other towns, like Panajachel. Go to Hotel Atitlán for a great and hefty meal.
Day six: visit a women's cooperative in a town around the lake. Use the tuc tuc service to travel around as the drivers are also great tour guides because they know their towns.
Etc etc.
And according to his/her question. He's just looking for ideas for some cool things to do with his/her time off.
It's so vague. Maybe the phrase you're looking for is it "broadens your perspective". Maybe something else.
And there are better places than Guatemala. Like Costa Rica.