This Shabbos is commonly called "Shabbos Breishis". On the surface, this seems to be referring to the fact that we read the Parsha Breishis. However, there must be a different reason. If this would be the purpose, every Shabbos would be referred to by the parsha read that week, for instance next week Shabbos would be called Shabbos Noach and the following week Shabbos Lech Lecha, and so forth. Why is this Shabbos more special than other weeks that it is referred to as "Shabbos Breishis"?
The Shinaver Rav relates, in the name of his saintly father-in-law the Arye D'bei Ilo'i, as follows: During the Aseres Y'mei Teshuvah many people undertake new kabbalos, taking upon themselves to improve in a certain area. Yet, one may sometimes feel that, because of his various misconducts of the past, any resolution to better himself are insignificant.
Hence, we call this Shabbos "Shabbos Breishis", which could be interpreted as 'the Shabbos of new beginnings'. This implies that everyone can and should leave their past behind them and start again 'from the beginning'. No matter what one may have done in the past, now, at the beginning of the year, he can turn over a fresh leaf, and serve Hashem with renewed devotion and commitment (דברי יחזקאל פר' בראשית).
Once, before kiddush on Friday night Shabbos Breishis, the Sanser Rav exclaimed: "Now is the time to start sorting out everything in a sustainable manner", and then proceeded to explain with a mashal. At the special market days, a merchant is busy buying any merchandise that appears to have potential value with the intention of selling it further and making a mark-up. However, he can not have proper peace of mind about what is really worthwhile in the long run and how to properly go about with his dealings. Only when things quieten down and he returns home can he begin thoroughly sorting things out.
The same is, concluded the Sanser Rav, with the holy days of Tishrei. We are busy with intense Avodas Hashem, ensuring to seize the opportunity of fulfilling every special mitzva that comes our way. These include shofar, the minhagin that are connected to teshuva and tefilla, sukkah, arba minim, dancing and rejoicing with the Torah etcetera. However, being so deeply engrossed in this intense Avodas Hashem, we may be lacking the proper mindset required to set out and ensure a long lasting effect and improvement. Therefore, now, when everything has calmed down, is the opportune time to sort out our 'investments'.