Stop in for a cup of coffee

Have a co-worker retiring, known him since my Navy days, met in 1983. Trying to think of a retirement gift, him and his wife love guns but he has an aresenal and I mean a LOT, any ideas? I was thinking either something from a new high tech shooting range they built or maybe a gift cert. from Skagit Arms, pretty decent local gun shop?
Just dawned on me you could get him a gift certificate to The Mag Shack. He sounds like he might be a guy that needs about a million different mags? And nobody likes spending money on mags!