Suffer the consequences

First:some background information.
An old friend (we will call him Jack) of mine is in this "relationship" with another friend of mine. it turns out that This other kid named Christian, a newer friend was fucking aroudn with this girl, behind my friends back and my friend found out on saturday and frankly isnt too pleased abtou the situation.

Allright, onto the present:
Today day stated out jsut fine, waking up at 11 because i dont have school. And two of my friends stop by and we go grab some lunch and chill out.
We go up to Christians house, because Jack and my other friend want to get sponsored by Christian's dad's company.

So we get up there and no one is home, so one thing leads to another and we are in his room playing a little joke. This joke is no big deal, we just put some yarn hanging around his room, and we put some other shit into a bag and put it back on the shelf...not a big deal right? WRONG.

Christian comes home, as we are leaving, so we peace it real fast. I get a text abotu a minute later threatening me saying that i sould go hide away for a while because of how pissed off he is.

Word gets around and about an hour later, i find out that he was telling people, including his dad, that we fucked up his ENTIRE house, putting string everywhere and creating total chaos all over. So i get a call from his dad, and i apologize because at this point, i realize that the timing is terrible and that i completely regret doing it. But his dad wants me and jack and my other friend to make it up to him. So i tell him sure, i will think of something.

So I come to you, Newschoolers, to ask for your advice on how to make it up to him.

Keep in mind that i apologized profusely and that I wsa threatened a second time after apologizing to Christian.

So
What do I do to make it up to him?
and please do not refrain from posting your opinions on the matter in general.