I don't know if anyone has heard the term or knows what "Everesting" is?

It's climbing the equivalent of Mount Everest (8 848m) in one bike ride. A cyclist who attempts it normally chooses a steepish climb and then goes up and down continuously until he/she has climbed more than 8 848m

Well, I had 2 mates that completed this feat this morning on a hill around the corner from me.
They started last night at 19:15 and after almost 15 hours in the saddle and cycling almost 256km over a period of 19 hours, their total cumulative ascent was 9 852m.