Well, im not sure if you want PvP or Regular fun characters, but if your looking for fun and 'semi' pvp, I think I remember some builds.
One is Frenzy Barb. Just load him with speed gear to a point that once fully charged up, your barb could possibly run around cow level in less than 20 seconds pretending his duration was endless (or he hits monsters along the way). I've tried this and well, its hilarious, especially with that vigor paladin aura

. Only downfall is, your running so damn fast its almost impossible to click on the monsters. PvP wise...well, I chase down sorcs almost as fast as they tele. (Unfortunately they still kill me cause they can teleport forever while I have speed duration run out).
Singing Barb, if you want is another build. I suggest the last two cries on the lower left, one that does damage and one that lowers defense.
Rangers, Paladin with a bow basically. Fanc and some bow, a ballista if your a bit poor on zon bows. If you can afford it, try a BOTD bow, it never hurts with fanc

. Also Hellcast with good sockets and Conviction. This build works in PvP to an amount, just make sure you get Enigma to be able to teleport away, its a lot safer.
Convertadin. Conversion + Thorns, the old non-hostile PKer on hardcore lol. Basically convert minions, then put thorns on them and the other monsters fighting you will hit them and take damage. It was fun in 1.09 but I haven't tested it on 1.10, so if you want, try away =D.
Swarm Necro. Although the build i stated before was for PvM, it can be taken into PvP. Just do not get more than 1 point into revive (since its a waste actually) Focus on warriors, mages and amp. (Lower resist is alright too but, mages are hard to keep alive). Use a might merc and have enigma teleport. Your goal is to teleport ON the character your fighting. Chances are, they'll be so stun locked from bombardment of attacks that they wont be able to retaliate easily. This build is not meant for barb fighting unless you Iron him!
Hybrid Assassin. This build is a bit on the hard side to pull off, since your not going to be a perfect Martial Artist or trapper, but it'll still be capable of dueling with. I suggest kickers because they are much more reliable in 1.10. Master Dragon Talon for kick damage and Lightning Sentry. Get all staples to assassins, including BoS, Mind Blast. Now thats 40 points used up so lets pretend 40 more is available (quest ones will make up for Prerequirements.). If you want to be leaning torwards martial artist, venom is good since it adds onto kick damage. If however, you have enough P scs and dont want waste points into venom, pump up a syn for a trap. Assuming you'll have 20 points available after, you can put them on skills that'll assist your assassin, such as BoS for Faster Trapping and Attacking and Claw Guard to block spells as a dual claw assy for anti-mages (optional). Some say to master dragon flight, but remember, no one really stands still, and the sorcs I duel with teleport as soon as they see your leg go up to kick so its a 30% chance of hit unless your fast enough to mind blast first. Cats Eye Amulet is required for its IAS. I good strategy is to find a weapon that has amplify damage on it too, since I've noticed it transfers to kicks.
Edit: Eek, forgot a build
Chargadin. Might + Heavy Hitting Weapon = Ow.
Last but Not Least...
Meleemancer. Completely incapable of pvp and almost pathetic against monsters. However, how often do you see a necro holding a BOTD two handed sword and showing up in a duel actually wanting to kill you with it? The thought itself is funny. But whatever, this is just a last resort if your extremely bored. Dont forget bonearmor, your seriously gonna need it. (Note: Never has been tested outside Normal Mode)
Edit: Well since Im editting might as well add that I wont say exactly where to put the remaining points after the 'specific' skills are mastered. Check what gear you have available and based on what your lacking / have, finish the build. Example: If your lacking in resistance and dont have shimmering scs, you'll be needed more elemental resistance than me.