Edit: I almost missed it, but Dragon magazine has recently published a very similar ritual to what I propose in this post. It's in the third Playing Vistany article, and it's called Comrades' Succor (no Compendium link yet, though). So, if you liked my idea, you can use it officially now. The ritual in Dragon actually allows to transfer surges instead of spending them, so I prefer my rule, but it's close enough.
Very often, my group has been forced to take an early rest due to one member or the other getting beaten hard, and unable to return to full HP (or even to consciousness). This usually leads to some awkward situations, and more than once our DM has resorted to handwaving the recovery of some surges to keep the game going, when having a long rest wouln't be feasible. Even if our characters might be able to beat more encounters without a full group, we find unacceptable to have a player out of the game until we can find a place to camp. What could we do to prevent this?
It is certainly possible to mitigate the problem through better tactics and character customization (in fact, some of our characters have picked the Durable feat with this in mind). However, you can't help having some PC's that are less resilient than the rest, and sometimes the fight just goes wrong, and someone gets knocked down. So I have been thinking of possible house rules that specifically address the problem of a character running out of surges.
Now, when messing with this kind of things, you run the risk of obsoleting the use of healing surges as a resource in the game. I don't want to do anything like that, even if there are already some powers, like Unicorn's Touch (which I have strongly criticized) that break this model (EDIT: No more! Unicorn's Touch has been errata-ed into a daily). What I wanted was a solution where surges would still be relevant, but a character without them could remain in the game, even if at a disadvantage. An additional restriction was that it should be easily accessible to any party, regardless of composition.
The idea I came up with meets these requirements, and has the unusual advantage of being implementable in an official book, without any need for errata. It's a low level ritual, with a game-changing impact not unlike that of Raise Dead:
You temporarily link the life energies of your allies, so that they can share their strength with an exhausted comrade.
Level: 1 Component Cost: 50 gp
Category: Restoration Market Price: 50 gp
Time: 10 minutes Key Skill: Heal (no check)
Perform this ritual during a short rest, and choose a target character with no remaining healing surges. At the end of the rest, you or any character assisting in the ritual can choose to spend any number of healing surges without gaining any hit points. The target regains hit points as if he had spent that many healing surges.
The raw lifeforce of paragon and epic characters is much harder to manipulate; increase the component cost to 1,000 gp for paragon tier characters, and 25,000 for epic tier characters.
The most important feature of this solution is that, by working only on surgeless characters, it prevents a character benefitting from it from using most common forms of in-combat healing until the group takes a long rest. This is a severe drawback, but a vulnerable character is a definite improvement over an unconscious one. This way, we not only ensure that surges remain relevant, but we also protect the Artificer's niche, as the healing mechanic of that class is very similar to this ritual's effect - with the crucial difference that the targets of an Artificer's infusion can still heal during encounters.