Unlike other seasons there are not that many beer styles that are specifically brewed to celebrate springtime. However there are a number of styles that are associated with the events and holidays of spring. And some styles just seem to taste better during springtime.
Maibock, or May bock, might be the only style of beer that is brewed specifically for springtime. And even this style is not unique to the season. Hellesbock is brewed throughout the rest of the year in Munich and Bavaria from a virtually identical recipe. Nevertheless, this light colored, wide bodied bock seems perfect for spring. The light color and refreshing lager snap of the brew seem perfect for the increasingly warm days. But it has a heavier body and generally higher alcohol content than other light colored beer styles like Pilsner.
Regular bock is also a very nice beer for springtime sipping. Its darker color speaks of a stronger malt flavor and full mouthfeel. All bocks are lagers so it has that refreshing zing but it's still lazy enough to spend some time with while watching spring creep over the world.
Finally, dopplebock played an important role in one spring-time ritual - Lent. The story goes that the monks of St. Francis of Paula who made Munich their home originally brewed the chunky beer to provide them sustenance while they observed Lent by fasting. Only later when the beer found its way to the general population was the double bock name given it. Until then it was known only as Salvator.
The black ale from Ireland has a very specific place in the celebration of St. Patrick's Day making it an important springtime beer. Sadly, Saint Patrick himself would have never had the chance to try stout himself; it was not invented until around a thousand years after Patrick died. But the beer has become a permanent part of the day named for him as both have come to represent Ireland and irishness to revelers all over the world every March 17th.
Although not specifically connected to spring, spiced beers with lighter profiles are nice during the season. Wit beers from Belgium are spiced with coriander and orange peel. These ales are light and refreshing while still full of flavor. Ginger beers are also very nice and will certainly wake up the senses.
Again, there's nothing particularly springy about fruit beer. However many breweries release seasonal fruit beers in the springtime and their arrival can be as welcome as springtime flowers. Often based on wheat beer recipes fruit beers can offer flavors from raspberry to peach to mango. When picking a fruit beer remember the fresher the better so pick one that was brewed nearby or, even better, fresh on tab at your local brewpub.