(Image: Courtesy of Google)

Google makes billions of dollars dishing out contextual ads. Its bread-and-butter search revenue makes it appealing to investors, but less so to tech enthusiasts and journalists, many of whom would rather hear about the search giant's forays into self-driving cars or micro-satellites than, say, the latest AdWord upgrade.

As in years past, Google is undertaking an ambitious array of business partnerships and tech projects in 2015. Some of these efforts have the more pragmatic goal of boosting the company's presence in growing mainstream markets such as enterprise cloud computing. Others are blue-sky initiatives, such as self-driving cars or low-orbit satellites designed to make the Internet accessible from just about anywhere on Earth.

Google's business is becoming increasingly diversified. For instance, there's the very successful Chromebooks venture, and the very unsuccessful Google Glass (which really isn't dead yet -- more on this in the slideshow), as well as the too-soon-to-tell Android Wear (software for wearables) and Android Auto (car tech).

What else is Google working on? One persistent rumor claims the company will soon offer its own wireless plan by reselling Sprint and T-Mobile services. If true, it's possible Google might act as a disruptive force by seriously undercutting the prices of the two top wireless giants, AT&T and Verizon. There's a precedent for this in the broadband market. Google charges just $70 per month for its 1000Mbps fiber-optic service, which is currently available in three US markets. Verizon, by comparison, charges $75 per month for its 75Mbps FiOS Internet plan, and $285/month for 500Mbps. So, if you fear you're overpaying for home broadband -- or what your ISP calls "broadband" -- you probably are.

Google's side projects are fun to watch, but they don't always contribute a lot to the company's bottom line. Advertising makes up about 90% of the company's revenue. Many of Google's experiments may seem kooky, but they're really designed to benefit Google's core ad business by bringing more Internet users online, many of whom will use Google Search. For instance,Project Loon, a proposed global network of high-altitude balloons for bringing wireless Internet to rural and remote areas, could help Google's core business a great deal.

We've summarized Google's top 2015 projects -- from the pragmatic to the peculiar