I've recently started playing a retro-clone game called “Adventurer Conqueror King” from Autarch. It's a great new take on old-style D&D, and I'll review it more in-depth later. Right now I want to share something I did in our first session as an example of what you can do to quickly build depth into new characters, only five-minutes into the game.
So we've got a shiny new group of adventurers. They area all currently live and work in the same geographic location (in this instance, a small town) and, if not friends, they have at least heard of each other. I take all the PC names and write them on slips of paper. I shuffle the names up and pass them pack to the players. I have the players look at the names but don't show anyone else. Any player who get's the name of his own PC should swap with the player next to him until everyone has the name of a PC that isn't theirs.
Now we go around the table. I look to Destiny's player.
GM: “Whose name do you have Destiny?”
Destiny's player: “Valmar's”
Valmar is a Neutral Human Mage.
GM: “Tell me a rumor that everyone has heard about Valmar.”
Destiny smiles; Valmar looks nervous.
Destiny: “Back when he was a teenager, Valmar killed his uncle with black magic.”
Now this rumor is established! People have heard this rumor, it exists, and there's nothing anyone can do about it. But, we turn to Valmar's player.
GM: “Valmar, is this rumor true? And if not, what's the true story?”
Valmar (lighting up): “I DID kill my uncle with magic, but what nobody knows is that he was killed then resurrected by an evil necromancer. He was a zombie when I blasted him!”
Excellent! Now, not only do we know a bit more about Valmar's past, we have an idea about what the community thinks about him, plus we have the seeds for a new NPC, an evil Necromancer with ties to Valmar's family.
I reward both players. Destiny gets 250xp for creating the rumor. Valmar gets 250 for accepting and/or clarifying the rumor. If they were higher level, I'd give them more XP. If we were playing QAGS, I'd give them Yum Yums. If FATE, Fate Chips. Reward your players in whatever currency works best for your game.
We continue around the table this way. Eventually every player should be rewarded twice. Once for creating a rumor, and once again for clarifying a rumor about their own character.
This worked great for my group, and within 5 minutes, before the game had even started, we had personality quirks and vague background stories already established for a fresh batch of PCs.
Give this technique a try with your own groups and let me know how it works!