I took these pics of both the Ritualist and Assassin From the first Preview Event which was geared for PvP. There are a couple of other events slated to hit so If you missed the first one, there will be others. A PvE or RPG type event is scheduled to be the next type of event to roll out. The other is most likely to be the Launch event of the game.
Ritualists:
This profession looks like a spin on Gypsie-type character. This character reflects the looks of other type of Shaman or Spirit summoners from many cultures like Native American or African healers. The Animation presented so far reflects a “VooDoo” like dance or stance to summon the spirits that are seemed to be bonded to the mortal world by Chains. These spirits actually struggle to escape since the summoner can also cause their demise. That’s right, there are skills that will sacrifice the spirit for the sake of your party’s well being offering some pretty neat health bonuses for doing so.
Assassin: 
This is one of the more interesting of the two because it introduces some very unique spells and skills to an already diverse game. Some of these skills actually require you to chain them in a specific order to do the maximum amount of damage to a foe. There are also speed enhancements and teleportation spells to get you out of tight spots very quickly. Assassins are allowed the default of an attribute called “Double Strike”. Double Strike guarentees you a chance of striking the enemy twice a swing. The higher the attribute the better the chance. The animation combined with the looks makes the Assassin seem like Anet’s inspiration was the one and only Naruto manga/anime series.
The recent PvP Preview event was only a small peak inside the game known as “Factions”, AND I expect to see much more at the second event.