My group has already run a few games using the beta rules and the Quick Start, and we're talking about some different concepts.
Imaginal States (run by fellow forum-goer TRNSHMN) opened with R-cell being assembled in Pennsylvania following a blitz-attack on a DG safehouse that left two friendlies dead, as well as one attacker; a second attack on the city morgue stole the corpse of the attacker. Like a lot of good DG scenarios, it ended with a building burning down, at least one of us in jail, most of us mentally rattled and one of us grimly marching into the forest with a half-loaded SMG to do futile battle with a worm-god.
Mutatis Mutandis, run by yours truly, took place in Wamego, Kansas. Spoiler warning, it was a Carcosa/King in Yellow scenario, so stuff got weird. Taking place immediately after the events of
this music video, it has led to me basically not being allowed near the Hastur Mythos again. Did you know Wamego, Kansas is where an
LSD kingpin had their lab in a literal missile silo? Did you know it's also got a pocket industry around the Wizard of Oz, so the colour yellow is
prominently featured? Did you know that nearby Tuttle Creek Lake drowned four towns when it was formed? Did you know that Hastur starts as a falconer, but ends a king? Did you know his war of usurpation
still rages? Well, H-cell sure found out the hard way as the walls of local reality started wearing a little thin...
Other ideas we've floated and are planning to run at some point using DG:
Blue Box is set around a DARPA-funded testing facility (its codename is the eponymous "Blue Box"), situated in a particularly anonymous and run-down part of North Dakota. Essentially, it's a warehouse full of mad science that periodically gets picked up, put on and studied to see if maybe it'll save a few soldiers' lives over in the Middle East, or make a better airport scanner. The security clearance requirements means the pool of testers is pretty small, and a bunch of them just went rogue - in the definition of "rogue" that involves raiding a nearby farm and leaving livestock entrails arranged in occult symbols across three fields. The poor unfortunates of our DG cell (ideally those with a military and/or scientific background) are tapped to essentially become replacement testers in order to figure out which of the many, many mad science projects in Blue Box accidentally went Mythos.
All Expenses is not a planned operation, rather an unfortunate confluence of events. During a luxurious conference on a Pacific island (your taxpayer money well-spent!) attended by various government agencies in relevant fields, strange things start happening. This being a large gathering of intelligence and law enforcement agencies, there are more than a couple of DG agents in the mix who realise just what species of south the conference is heading when a local astrophysicist very publicly commits suicide rather than "be here when it comes". As a panic breaks out among the convention-goers and things start going a bit Dead Island, the DG cell have to make do with what's at hand as they come up against a rising threat. (Why didn't we think to pack the flamethrowers?)