How Can I Get Ink Pen Stain Out Of My Leather Sofa?

Cologne is by far the best way to get ink stains off your couch, but ONLY if you follow these instructions!
NEVER spray your leather couch directly with cologne, and NEVER let is sit! Yes it will remove ink stains, but it will also fade the color.
Instead, spray your index finger with cologne and rub it on the ink stains. Repeat as necessary.
Works like a charm

Ink on my white leather car seats, how do I get it out?

I used the hairspray idea and holy crap it worked

Try hairspray.  it helps remove ink stains from clothing, it'll probably work on your couch.

In the automotive section at Walmart they sell Leather cleaner / conditioner wipes in a canister....kinda like baby wipes.  It worth a shot.