There are a bunch of "special encounters", which are IMHO of very little use or relevance to the game. If THESE are the ones the "explorer" perk is supposed to help find, then I'd say you can safely skip that perk.
"Bridge of Death". It helps if you've seen Monty Python. Answer the first two questions correctly, BUT answer with a question the third time. If you just answer right, the keeper will let you pass, and that's all. But if you answer with the question, he'll die, and you can get his robe. The robe has the same protection values as Combat Armour, at less than half the weight. (You can't use it for combat implants, though.)
"King Arthur's Knights". Another Monty Python plug. Answer "yes" when they ask about the holy hand grenade of Antioch, and point them in a bogus direction. You'll get a plasma pistol as a reward. (I still fancy killing and looting them instead, but each time I was still too weak to stand a chance against a whole miningun squad in power armour :)
"Cafe of Broken Dreams". Roland Ng says you can get Dogmeat from Fallout 1 in your group here. I didn't try it, and anyway I had my group full already. Try for yourself.
"The Unwashed Villagers Hunting a Spammer." Nothing much to do here, except watch the execution and get a few stimpacks from a hidden locker. Or, my favourite, you can slaughter them all and get their weapons and ammo. They're worth just 1xp each, though, and they are too many and too tough if you meet them too early.
"A Talking Stone Head". You can keep clicking on it until you get a monument piece. It takes a lot of clicks, so keep at it. Allegedly, you can use it to temporarily increase your stats. I didn't try it.
"A Guardian Portal". Enter it, and you'll be transported to Vault 13, only 80 years ago. (I.e., when Fallout 1 happened.) If you click on their computer, it says you broke their water chip, and the vault will run out of water in 150 days. (The start of the Fallout 1 plot :) It'll also give you 1000xp and transport you back to the present day. So be sure to do all the looting before trying that.
"A crashed federation shuttle." You can get three hypos from the corpses. Allegedly they can heal you to full hp. I tried them when I was at full hp, and they didn't do anything. So I mistakenly assumed they were useless, and dumped them in the car trunk.
"A tin woodsman". Actually, he looks to me suspiciously like an Enclave trooper in Advanced Power Armour. Get the oil can, use it on the bugger. He'll give you 150 micro-fusion cells.
There's a merchant party you'll sometimes meet, which I suspect is also a special encounter, although it doesn't have a funny name. First time the merchant will sell you the Alien Blaster from Fallout 1. There are better energy weapons in Fallout 2, anyway. BUT if you bought it and if you meet him a second time, I _think_ he'll sell you the Red Ryder LE BB gun, which is a very good weapon for a while. (I.e., until you find better weapons :) This sequence happened to me only once, so I may well be wrong.