I haven't noticed that it recovers on the weekend more than any other time, but if it did, maybe it's because most institutional investors aren't at their desks to knock the price down. I think that a lot of price manipulation comes from wall street (especially since futures contracts were established) and it causes the prices to be misrepresented. Bitcoin grew organically on its own for the first several years, but once it hit mainstream and everyone started buying it, things started getting a little blurred. Central banks are probably printing money and then using that money to employ traders to short the coin.

Or it's just more people at their computers during their free time, like mentioned above.