We were in the process of buying a home; it was a short sale so the whole process was very difficult (especially on her as she is a part time realtor, and was doing loads of stuff to make the sale happen in addition to her regular job). Anyway, on that day something had happened where we thought we'd lost the house, and we were both kind of down. I had the ring already and was planning on waiting until our upcoming holiday to the Caribbean, but on that day I was just overcome with how much I loved her and how much she loved me and how hard she was working to help set up our life together, so I decided it was go time.
I suggested a walk in the park; there were these trails through the woods that I had grown up walking. I waited for the trail to be clear of a few kids on bicycles and after pump-faking a few times to tie my shoe, went down on one knee and did the damn thing. Those kids did ride past again at some point and probably wondered who that weird guy was on his knees hugging his girl around the legs in the middle of the woods. A good day.