You can take a 15 min outrigger boat ride to the volcano that is within the lake. As you head from Tagaytay city toward the lake, many touts may jump in front of your vehicle offering boat rides - they take a commission. If you know where to go, however, you can catch a boat directly from the boat owners. Once on the island you will be herded onto a donkey and driven up to the rim of the crater around 30mins. It's a rather unpleasant, environmentally-damaging ride, but the view at the top is quite spectacular. The option of hiking to the top is not encouraged.
Philippine Adventures (http://www.philippineadve...) provides scenic city tours from Metro Manila to Tagatay with the option of catching a boat ride to Taal Volcano and hiking to the spectacular Taal Crater Lake.
Wedding in the sky - The atmosphere and scenery of a Tagaytay destination setting provides a special character to the wedding. An hour and 15 minutes drive through South Superhighway or Coastal Road, Tagaytay offers different venues for different settings that will suit your taste.