The verse ascribed to Vishvamitra in the third book of the Rigveda is a single sentence: it invokes the excellent radiance of the sun god Savitr and asks that he stimulate our thoughts. It became the most repeated verse in Hinduism, recited at the morning and evening junctures of the day and given to a boy at the thread ceremony that admits him to Vedic study. For most of recorded practice, receiving it was restricted to the three twice born classes, and reform movements from the nineteenth century onward have argued about extending it.
The irony is not accidental to the story. The mantra that gate keeps brahminical initiation is credited to the one figure the tradition holds up as having entered that status from outside it.
The same book of stories keeps his failures alongside it. Sent to break his austerities, the apsara Menaka lives with him for years and bears Shakuntala, whose son Bharata gives his name to the country in the epic's reckoning. Later the apsara Rambha is sent on the same errand and he curses her to stone, and the anger costs him again.
Trishanku is the sharpest of them. A king wanted to enter heaven in his own body, was refused by Vasishtha and by the gods, and Vishvamitra took the case, sent him up by the force of his austerities, and had him thrown back down by Indra. He held the falling king in mid air and began building a rival heaven around him. It was stopped by negotiation, and Trishanku hangs there still, which is why the phrase means a condition suspended between two places with no way into either.