Each week, former sf.myopenbar.com editor Allie Pape brings you her picks for the best places to booze on the cheap in SF. This week: Pitchers of margaritas, fifty-cent oysters, and a taste of Amsterdam. Have an event coming up? Want to share a tip? E-mail her.

1. Amsterdam Live: As part of its ongoing campaign to remind drinkers of its Dutch origins, Amstel Light is hosting a promotional event meant to represent "true Amsterdam style." DJs, art, and of course, plenty of free beer make up the offering. (We know what you're thinking might be missing, and no, they won't have that.) Join the fun by RSVPing here; you get an automatic +1. (Thursday, August 6, 8 pm, at Ruby Skye, 420 Mason St., Union Square.)

2. Wine Challenge: Many of us have special talents, and bars have been known to capitalize on these from time to time: open-mic nights for aspiring singers, wet T-shirt contests for the well-endowed, and your LTB correspondent's personal Achilles' heel, trivia night. Oenophiles, however, have been left out in the cold, until now. The deal is simple: buy a $25 wine flight at Ame, correctly identify the grape varietal from which each wine was made (the grape names are given to you), get said wine for free. For most of us, this is a dicey proposition, but if you know your vintages, it should be a cakewalk. (Nightly through the end of August, 6-9:30 pm, at Ame, 689 Mission St., SOMA.)

3. 50-Cent Oysters at Zuppa: In the continued battle for happy hour supremacy, $1 oysters have become a fairly regular fixture at a number of bars (from swanky 5A5 all the way to divey El Rio). Zuppa, however, has busted this one wide open: their happy hour oysters are now a mere 50 cents. A dozen oysters for $6, plus $4 beer and wine? This is a trend we can get behind. (Monday-Friday, 5-7 pm, at Zuppa, 564 4th St., SOMA.)

4. Bossa Nova Happy Hour: This chic Brazilian restaurant, tucked away on the corner of 8th and Minna, boasts a combo of itty-bitty portions and staggeringly high prices-- making it far from our usual stomping grounds. However, times are changing, and Bossa Nova now offers a happy hour with their signature mojitos and caipirinhas for only $5. If you've never had a caipirinha, (made with cachaca, a Brazilian sugarcane liqueur), you're missing out on one of the world's great fast-lanes to extreme drunkenness. (Tuesday-Sunday, 5:30-7:30 pm, at Bossa Nova, 139 8th St., SOMA.)

5. Parrilla on Polk: Speaking of extreme drunkenness, this Latino restaurant boasts the following stats: $8 pitchers of margaritas and sangria, $2 beers, offered for four hours, located in Polk Gulch. You can take it from here. (Monday-Friday, 4-8 pm, at Parrilla on Polk, 1760 Polk St., Polk Gulch.)