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The keyword "#*$!Activities" gets over 5,000 visitors per month through overture, while "#*$!games" gets over 3,000.
Alternatively, I could do a find/replace changing "activities" to "games" and still keep the registered domain. But the article will look a bit weird. What do you think?
Look at your 100 pages, and go with the title that fits best (assuming that you are sticking with that content). Choose the name that will make sense to your visitors.
Neither #*$!activities.com or #*$!games.com will make a great impact on anything; even #*$!-activities.com or #*$!-games.com will not make a significant dent in the serps.
With 100 pages, you should be able to target 100 key phrases, while you will fail to target one word. Anyway, how many of your visitors will search for 'games' or 'activities'? Not many.
Remember that SEs index pages, not sites - make EACH and EVERY page work to anticipate many searches, don't obsess over ONE SEARCH.