Various food/wine/beer kiosks are set up throughout the World Showcase and for a nominal price ($1.50-3.50) you can sample an appetizer at the booths of your choice. For slightly more, you can sample a small glass of wine.
There are also numerous special events, such as wine tastings, tea tastings, cooking seminars, etc. that are free (prepare to come to the event very early and stand in line for a long time!)
Finally, there are a variety of ticketed events such as food and wine pairings at restaurants, that generally sell out very quickly despite being fairly pricey.
Oh yeah, and there are fun retro concerts every night (DH and I saw Cool and the Gang 2 years in a row and Three Dog Night the year previous).
DH and I did a free tea tasting last year and really enjoyed it, but generally we are happy to just make the rounds of the World Showcase, sampling various ethnic food and wines. It's really a blast, and definitely a "festival" atmosphere.