The Welcoming Committee (née Guerrilla Queer Bar) has been taking over traditionally “straight” bars in this city for almost a decade, gathering LGBTQ revelers to flash mob, say, some Fenway sports bar and make it more fabulous for one night. The third Saturday of each month, one of those events is just for the ladies (though men are more than welcome, of course). Flannel Takeover Company has stormed everywhere from the Burren to Common Ground, ensuring that Boston’s lesbian scene stretches from Somerville to Allston. Flannel optional, fun guaranteed.