Below is a compilation of readings from various sources about 立春.
Spring season begins today on Chinese calendar, we call it 立春 or Li Chun, meaning the beginning of spring. On this day, people usually go outdoors, make paper-cuttings to decorate windows, and eat spring egg rolls filled with fresh vegetables inside, it’s called 咬春, meaning bite spring.source: http://my.opera.com/Aprilsnow/blog/the-first-day-of-spring
The real importance of this day resides on its agricultural implication – soon farmers will start to plow the soil preparing to seed. China has a long and well-developed agricultural history, people’s lives are very much involved with agriculture, and spring is considered a season for plantation (春耕) while summer is called growing season (夏长), autumn harvest time (秋收) and winter for reservation (冬藏).
Spring is so special, it always reminds us of life, renew and hope. So we celebrate it on its first day.
所 谓“咬春”，就是在立春这一天吃一些春天的新鲜蔬菜，既为防病，又有迎接新春的意味。有记载道：“立春日，食芦菔、春饼、生菜，号春 盘”， 还有：唐人于“立春日作春饼，以春蒿、黄韭、蓼芽包之”；到了南宋，宫廷中的春盘，除“春饼”外，还有“翠缕红丝、金鸡玉燕，备极精 巧，每盘值万钱”。杜甫的《立春》诗写道：“春日春盘细生菜，忽忆两京梅发时。”苏东坡的《送范德孺》诗写道：“渐觉东风料峭寒，青蒿黄韭试春盘。”都提 到“春盘”，指的就是立春这天吃的新鲜蔬菜。
Another thing that is interesting is if direct translate the word “Li Chun” 立春, “Li” 立 means STAND. “Chun” 春 has a lots of meaning and one of it is represent egg. So, “Li Chun” 立春 means “Stand Egg”.According to the saying, the egg should not be refrigerated and must use raw egg. I have tried to make a few eggs stand and the eggs continue to stand on till the next day. I am not sure whether the saying is correct as I never tried it on any other days. So I am not sure whether the egg will stand on any other days but it is indeed a good experience and knowledge. You could use this to impress or surprise your kids, family or friends in the next Chinese New Year. Perhaps you could make the egg stand together with your family members as a bonding activity. This is another fun activity during the Chinese New Yearsource: http://swanthamsw.blogspot.com/2011/02/how-li-chun-relates-to-egg-standing.html
No physical influence of other celestial bodies on the egg can affect its balance to the extent required by the folk belief. Gravitational and electromagnetic forces, in particular, are considerably weaker and steadier than the disturbances created by the person's breathing and heartbeat.
In 1947, Japanese physicist Ukichiro Nakaya verified experimentally that eggs in fact can be balanced with ease at any time of the year. He noticed that the shell of an egg usually has many small bumps and dimples, so that, by turning the egg in different directions, it can be made to touch a flat surface on three points at once, in many ways. It is not hard to find an orientation such that the triangle spanned by the three contact points lies right under the egg's center of mass, which is the condition for balancing any object. Of course, balancing an egg on a rough surface is easy too, for the same reason.
Martin Gardner also observed that "if you are convinced that an egg will balance more easily on a certain day you will try a little harder, be more patient, and use steadier hands. If you believe that eggs won't balance on other days, this belief is transmitted subconsciously to your hands", and compares the process to the "Ouija-board phenomenon".