Have you seen those "As Seen on TV" Aqua Globes? If not, here's a thumbnail: they're glass bulb stakes that you fill with water and then insert into the dirt next to a plant which 'self-waters' the plant for, they say, up to 2 weeks. They're not terribly expensive, (you can buy a pack of 2 on Amazon for about $13), but the DIY version is really the way to go. Because they're made using wine bottles, they hold a lot more water and the glass is much more durable. Hometalk holds our hand through the entire tutorial, taking us from wine bottle and copper fittings/tubing to finished product.
BUT, if you'd rather skip the plumbing works and do SEMI-DIY, check out this Nanny Stake from UncommonGoods. You simply insert a wine bottle into the terra cotta stake and you're done. Sold in sets of 4 for $17 for use with wine bottles, but they do have a set for $15 that is used for plastic bottles.
Maybe it's the terra cotta planter/stake & green ivy/bottle combos, but I find this most aesthetically pleasing.