1. The gematria for טוב לך is also 67. These two words can be translated as "good for you". This is the essence of אלול, it is simply "good for us". We can use an example to get a better idea. When a doctor tells you that it is good for you to drink many cups of water a day, we are more inclined to drink water. So too during אלול, this month is good for us. Why? Because as mentioned above, it is an opportunity for us to wake up and take a look at ourselves. Not many religions have a time period built into their colander that gives its followers this opportunity. Not only is אלול good for us, but it seems like Judaism is good for us too! Their is a passuk in Tehillim 128:2 that says "יגיע כפיך כי תאכל אשריך וטוב לך״- "if you eat the toil of your hands, you are praiseworthy, and it is good for you." This verse implies that those who work hard are praiseworthy, and the hard work is good for you. Now take the context of this passuk and apply it to the essence of אלול. Those who work hard to change themselves during is אלול is praiseworthy, and better yet the change is good for you. Any change for the better during this month is helpful in insuring that we are granted a good upcoming year. Going deeper into this concept the Rambam's Mishna Torah (Hilchot Talmud Torah 3:11) gives us another stance on טוב לך. Quoting Tehilim it says "אשריך' בעולם הזה, 'וטוב לך' לעולם הבא שכולו טוב' ", "you are 'praiseworthy' in this wold, and it is 'good for you' in the next world which is complete good." This gives us an ever bigger incentive to change. From here we can deduce that the toil done in אלול helps us not only in this world, but in the next world as well, where the reward is far greater and quite unimaginable.
2. Just like the gematria for אלול, the gematria for בינה is also 67. בינה translates as wisdom and understanding. אלול is a good opportunity to use one's understanding and wisdom. אלול is a person's opportunity to take stock of what he did during the year. Did he live up to attempts to change from the previous אלול? Or did he return to his normal ways once אלול, Rosh Hashanna, and Yom Kippur passed? If a person truly has wisdom and intellect he will not easily fool himself. Many times a person is willing to judge himself easily. Many times a person is willing to justify his bad behavior and sins. But one who truly has בינה will be able to look inside himself and judge himself as a man, not easily justifying his faults. Here we see the role בינה plays in the month of אלול.
3. On a lighter note, the modern Hebrew word for bathtub also has the gematria of 67. This word is אמבטיה. One can view אלול as a "spiritual bath", and we prepare to cleanse our sins during the upcoming High Holidays.
With this new spin on the month of אלול, I hope that all of Klal Yisrael seizes the opportunity to wake up from the blasts of the Shofar this month. Shana Tova!