Sunday, June 21, is doing double duty this year, as both Father's Day and the summer solstice. If you're curious about the day, check out The History Channel's collection of material about Father's Day. Topics include a brief history of this holiday (which was not instituted as a national observance until 1972), famous TV dads, fun facts, video clips, and photos of famous dads such as Paul McCartney, Elvis Presley, Jackie Robinson, and Muhammad Ali.
The kids' site Kaboose has a good Father's Day section, too, including some ideas for celebrating the day.
Fathers Day Celebration is another information-filled sites, with suggested activities and readings for the day.
And to celebrate the solstice, check out EarthSky's page on the event. The solstice is commonly called the first day of summer, although it's an astronomical, not a climatological, event (climatologists have their own ways of determining seasons). Most importantly, it's the day with the most daylight: from Monday on, hours of daylight grow progressively shorter. Celebrate by getting up to see the earliest sunrise of the year, or by playing ouside until dark!