The sprawling and impressive Cambodia Vipassana Dhura Buddhist Meditation Centre is near base of the western staircase up Phnom Preah Reach Throap. Foreigners are welcome to practise meditation here with experienced monks or nuns for one or several days. Meditation sessions are daily from 7am to 9pm and from 2pm to 5pm. In between you can hang out in the library, which contains scores of books on Buddhism not to mention an impressive collection of pirated Lonely Planet books. The en-suite guest rooms are fairly comfortable by monastic standards, albeit they are sans mattresses (wicker mats are as good as it gets). You'll be fed breakfast and lunch, but no dinner. There is no fixed price for a meditative retreat here, so donate according to your means; US$25 per day would be considered about average. Meditation sessions are free.