- Abulafa: 10 Word Adventure Synopsis's, Dungeon Seed, Encounter-a-day, Scenario's, Quick NPC's, NPC, One Sentence NPC's, Towns, Location Encounters and a lot more.
- Roleplaying Tips: One sentence NPC's, (non random)5 Room Dungeons.
- Asmor: Encounter Generator, Treasure Generator, Seeds, and several other very useful 4E tools.
- StolenCitadel Dungeons, NPC's, Plots, Locations, and Societies.
- Forbiden Kingdom: A simple seed generator.
- DM Tools: NPC's, Benign Encounters, Mercenary Missions, and Towns.
- WotC: Adventure seeds.
- Gozzys Dungeon Map Generator.
- Jame's NPC generator
- Dungeon's Unlimited (non-random) Map Index.
- TV Tropes:(possible mature content, and spoilers) Plots, Universal Tropes, Characters (as a plot device). Curses be upon the Chatty DM for spreading this evil, evil time sucking site to the gaming world.
- Story Spinner is a story starting generator but it can be useful for creating the "box text" of the adventure.
Sometimes a less "gaming specific" source of inspiration is more useful to jump start my creativity, to prevent me from settling into the standard Tavern/Clearing in the Woods/Dungeon tropes. These links are good for finding new ideas, though they may take more effort on your part to turn the ideas into something "game-able".
- Random Wiki Page: The page Title or subject is the title for you next adventure, or encounter.
- Random Fliker Photos: (potential exists for encountering mature content). Possibly the second or third photo is the subject or location of the adventure.
- Quotations: Maybe the top quote documents or characterizes the motivation of the actors.
- Stuck in Customs: (non random, updated daily), The top photo is the setting of an important event.
- Random Irregular Webcomic: Mix and match the settings and dialog.
- XKCD random comic: (some mature and mathematical stick figure content)
- Word of the Day: Quotations Page, Merriam-Webster (daily updates); If you combine the two words together you might have a title.
- Open the Monster Manual and flip to a random monster, this will be the "Villian" of the adventure. (I got Goblin Hexer)
- Grab a book (even non gaming) and flip to a random page, the middle paragraph indicates what the plot or focus of the adventure. (It was a pragmatic choice).
- Grab a Campaign Setting or Adventure, either one of your own or a published one and reuse the map contained with in, but rotate it 90 degrees.
- Start writing.
Also you can just start writing what ever gibberish comes to mind. What you write may not be game related in any way but at least the blank page monster is dead.