The guys are playing a sport.
a boy on a pogo stick takes a dive
It refers to multiple guys as opposed to just one boy, and a sport doesn't usually include playing on a pogo stick.
exists e1 x1 x2.(n_guy(x1) & Theme(e1,x2) & Actor(e1,x1) & v_play(e1) & n_sport(x2))
exists e1 x1 x2 x3 x4.(Theme(e1,x4) & Actor(e1,x1) & v_take(e1) & n_dive(x4) & on(x1,x2) & n_stick(x2) & of(x2,x3) & n_pogo(x3) & n_boy(x1))