Fishing trips.

Sounds promising.

The effects of eating ichthyoallyeinotoxic fishes, such as certain mullet, goatfish, tangs, damsels and rabbitfish, are believed to be similar to LSD, and may include vivid and terrifying auditory and visual hallucinations. This has given rise to the collective common name for ichthyoallyeinotoxic fishes of "dream fish". [...]

One of the men, a 40-year old, was admitted to hospital suffering from a digestive problem and frightening visual and auditory hallucinations, which took 36 hours to disappear. The second man, a 90-year old, suffered from auditory hallucinations a couple of hours after eating the same species of fish, followed by a series of nightmares over the next two nights. The poisoning can start to cause vivid hallucinations within minutes of eating a poisonous fish and may last for days, often with no other effects. There is no antidote. [...]

Indoles, with similar chemical effects to LSD (lysergic acid diethylamide) are believed to be responsible and may be consumed when the fish eat algae or phytoplankton containing the chemicals. All of the species effected by ichthyoallyeinotoxism are algal grazers. Others have claimed that different species of ichthyoallyeinotoxic fishes, such as Kyphosus fuseus, contain much more potent hallucinogens, such as dimethyltryptamine or DMT, which is considered to be one of the world's most mind-bending hallucinogenic chemicals.

(via BoingBoing)