Lagarfljót is a wonderful place to enjoy some time away from the hustle and bustle of everyday life. See if any water activities are available here, or just enjoy the calm ambiance.
You'll have sightseeing choices galore when staying in Egilsstadir. Lagarfljót is a great place to start here, but there are lots of other fine attractions to experience. Vök Baths, and East Iceland Heritage Museum are close to the body of water and and will cap off your day nicely.